JPWO2008069209A1 - Plasma display apparatus and driving method thereof - Google Patents

Abstract

At the time t1 immediately before the first SF (subfield), the voltage of the sustain electrodes (SU1 to SUn) is lowered from Ve1 to the ground potential. Then, at the start time t2 of the initialization period of the first SF, a pulsed positive voltage Vd is applied to the data electrodes (D1 to Dm). Immediately before this, a large amount of negative wall charges are accumulated on the sustain electrodes (SU1 to SUn), and positive wall charges are accumulated on the data electrodes (D1 to Dm). By applying the pulsed positive voltage Vd, a strong discharge is generated between the sustain electrodes (SU1 to SUn) and the data electrodes (D1 to Dm). Thereafter, at time t3, application of the ramp voltage to the scan electrodes (SC1 to SCn) is started, and an initializing discharge is generated between the scan electrodes (SC1 to SCn) and the sustain electrodes (SU1 to SUn). .

Description

  The present invention relates to a plasma display device that selectively discharges a plurality of discharge cells to display an image and a driving method thereof.

(Plasma display panel structure)
A typical AC surface discharge type panel as a plasma display panel (hereinafter abbreviated as “panel”) includes a large number of discharge cells between a front plate and a back plate arranged to face each other.

  The front plate includes a front glass substrate, a plurality of display electrodes, a dielectric layer, and a protective layer. Each display electrode includes a pair of scan electrodes and sustain electrodes. The plurality of display electrodes are formed in parallel to each other on the front glass substrate, and a dielectric layer and a protective layer are formed so as to cover the display electrodes.

  The back plate includes a back glass substrate, a plurality of data electrodes, a dielectric layer, a plurality of barrier ribs, and a phosphor layer. A plurality of data electrodes are formed in parallel on the rear glass substrate, and a dielectric layer is formed so as to cover them. A plurality of barrier ribs are formed on the dielectric layer in parallel with the data electrodes, and R (red), G (green), and B (blue) phosphor layers are formed on the surface of the dielectric layer and the side surfaces of the barrier ribs. Has been.

  Then, the front plate and the back plate are arranged opposite to each other so that the display electrode and the data electrode are three-dimensionally crossed and sealed, and a discharge gas is sealed in the internal discharge space. A discharge cell is formed at a portion where the display electrode and the data electrode face each other.

  In the panel having such a configuration, ultraviolet rays are generated by gas discharge in each discharge cell, and the R, G, and B phosphors are excited by the ultraviolet rays to emit light. Thereby, color display is performed.

  The subfield method is used as a method for driving the panel. In the subfield method, one field period is divided into a plurality of subfields, and gradation display is performed by causing each discharge cell to emit light or not emit light in each subfield. Each subfield has an initialization period, an address period, and a sustain period.

(Conventional panel driving method 1)
In the initialization period, weak discharge (initialization discharge) is performed in each discharge cell, and wall charges necessary for the subsequent address operation are formed. In addition, the initialization period has a function of reducing discharge delay and generating priming for stably generating address discharge. Here, priming refers to excited particles that serve as an initiator for discharge.

  In the address period, scan pulses are sequentially applied to the scan electrodes, and address pulses corresponding to image signals to be displayed on the data electrodes are applied. Thereby, address discharge is selectively generated between the scan electrode and the data electrode, and selective wall charge formation is performed.

  In the subsequent sustain period, a predetermined number of sustain pulses corresponding to the luminance to be displayed is applied between the scan electrode and the sustain electrode. As a result, a discharge occurs selectively in the discharge cell in which the wall charge is formed by the address discharge, and the discharge cell emits light.

  Here, in the initialization period, in order to generate a weak discharge in each discharge cell, the voltage applied to each of the scan electrode, the sustain electrode, and the data electrode is adjusted.

  Specifically, in the first half of the initialization period (hereinafter referred to as the rising period), a ramp voltage that rises slowly is applied to the scan electrode while the voltage of the data electrode is held at the ground potential (reference voltage). . Thus, a weak discharge is generated between the scan electrode and the data electrode and between the sustain electrode and the data electrode during the rising period.

  In the second half of the initialization period (hereinafter referred to as a falling period), a ramp voltage that gradually decreases is applied to the scan electrode while the voltage of the data electrode is held at the ground potential. Thus, a weak discharge is generated between the scan electrode and the data electrode and between the sustain electrode and the data electrode during the descending period.

  As described above, for example, Patent Document 1 discloses a panel driving method in which a ramp voltage or a voltage that increases or decreases stepwise is applied to the scan electrode during the initialization period. As a result, the wall charges accumulated in the scan electrode and the sustain electrode are erased, and the wall charges necessary for the write operation are accumulated in each of the scan electrode, the sustain electrode and the data electrode.

  However, in practice, a strong discharge may occur between the scan electrode and the data electrode during the rising period. In this case, a strong discharge is generated between the scan electrode and the sustain electrode, a large amount of wall charges and a large amount of priming are generated in the discharge cell, and a strong discharge is easily generated even during the descending period.

  When a strong discharge is generated during the initialization period, wall charges accumulated in the scan electrode, the sustain electrode, and the data electrode are erased. Therefore, an appropriate amount of wall charges necessary for address discharge cannot be formed on each electrode.

  In view of this, Patent Document 2 discloses a panel driving method that prevents the occurrence of strong discharge during the initialization period.

(Conventional panel driving method 2)
FIG. 19 is an example of a panel drive voltage waveform (hereinafter referred to as a drive waveform) using the panel drive method of Patent Document 2. FIG. 19 shows waveforms of drive voltages applied to each of the scan electrode, the sustain electrode, and the data electrode during the sustain period, the initialization period, and the address period.

  As shown in FIG. 19, the data electrode is kept at a voltage Vd higher than the ground potential during the rising period of the initialization period.

  In this case, the voltage between the scan electrode and the data electrode is smaller than when the data electrode is held at the ground potential. Accordingly, the voltage between the scan electrode and the sustain electrode exceeds the discharge start voltage before the voltage between the scan electrode and the data electrode.

  Thus, during the rising period, priming occurs due to the weak discharge that occurs between the scan electrode and the sustain electrode. Thereafter, a weak discharge is generated between the scan electrode and the data electrode, so that wall charges necessary for an address operation are formed on each of the scan electrode, the sustain electrode, and the data electrode.

For example, at the start of the address period of FIG. 19, negative wall charges are accumulated on the scan electrodes and positive wall charges are accumulated on the data electrodes. As a result, the address discharge in the address period is stabilized.
JP 2003-15599 A JP 2006-18298 A

  By the way, in recent years, the number of discharge cells (increase in the number of pixels) is increased and the distance between adjacent discharge cells is reduced as the screen is enlarged and the definition is increased. As a result, as will be described below, crosstalk is likely to occur between adjacent discharge cells.

  As shown in FIG. 19, the voltage of the sustain electrode is raised after a predetermined time (phase difference TR) since the voltage of the scan electrode is raised to Vcl at the end of the previous subfield. Thereby, an erasing discharge is generated between the scan electrode and the sustain electrode, and the positive wall charge accumulated in the scan electrode and the negative wall charge accumulated in the sustain electrode are erased or reduced.

  Next, in the rising period of the initialization period, a ramp voltage that gradually rises is applied to the scan electrode while the data electrode is held at the voltage Vd. Accordingly, after a weak discharge is generated between the scan electrode and the sustain electrode, a weak discharge is generated between the scan electrode and the data electrode. As a result, negative wall charges are accumulated on the scan electrodes, and positive wall charges are accumulated on the sustain electrodes. At this time, positive wall charges are accumulated in the data electrode.

  Further, during the fall period of the initialization period, a ramp voltage that gradually falls is applied to the scan electrode while the data electrode is held at the ground potential. As a result, a weak discharge is generated between the scan electrode and the data electrode and between the sustain electrode and the data electrode. As a result, the negative wall charges accumulated in the scan electrodes are reduced, and the positive wall charges accumulated in the sustain electrodes are reduced. At this time, positive wall charges are accumulated in the data electrode.

  In this way, at the start of the address period, negative wall charges are accumulated on the scan electrodes and positive wall charges are accumulated on the data electrodes. In this state, a negative address pulse is applied to the scan electrode and a positive address pulse is applied to the data electrode in the address period. In this case, the wall charge increases the voltage between the scan electrode and the data electrode, and the address discharge is stably generated between the scan electrode and the data electrode.

  At this time, since positive wall charges are accumulated in the sustain electrode, a large address discharge is generated between the scan electrode and the sustain electrode. Accordingly, when the distance between adjacent discharge cells is small, crosstalk occurs between adjacent discharge cells, and erroneous discharge is likely to occur. Therefore, in order to prevent the occurrence of such crosstalk, a panel driving method described below has been put into practical use.

(Conventional panel driving method 3)
FIG. 20 is an example of a panel drive waveform for preventing crosstalk occurring between adjacent discharge cells. Also in this example, the data electrode is kept at the voltage Vd higher than the ground potential during the rising period of the initialization period.

  In the drive waveform of FIG. 20, the phase difference TR for erasing discharge is smaller than the phase difference TR for erasing discharge in the driving waveform of FIG. The smaller the phase difference TR, the weaker the erase discharge. Therefore, in the drive waveform of FIG. 20, the erasing discharge is weaker than that of FIG. 19, and a large amount of positive wall charge remains in the scan electrode and a large amount of negative wall charge remains in the sustain electrode before the initialization period. . Thereby, the address discharge in the address period can be weakened. As a result, it is considered that crosstalk between adjacent discharge cells can be prevented.

  However, according to experiments by the present inventors, it has been found that the following phenomenon actually occurs. As shown in FIG. 20, in the rising period of the initialization period, a ramp voltage that gradually increases from the voltage Vm by the voltage Vset is applied to the scan electrode, the sustain electrode is kept at the ground potential, and the data electrode is kept at the ground potential. Is maintained at a high voltage Vd.

  As described above, many positive wall charges are accumulated in the scan electrodes and many negative wall charges are accumulated in the sustain electrodes before the initialization period. Therefore, when the voltage Vm is applied to the scan electrode, a strong discharge is generated between the sustain electrode and the data electrode, and accordingly, a strong discharge is generated between the scan electrode and the sustain electrode.

  Due to the occurrence of such strong discharge, the wall charges accumulated in the scan electrode, the sustain electrode and the data electrode are erased. As a result, even when a ramp voltage rising by the voltage Vset is applied to the scan electrode, the voltage between the scan electrode and the sustain electrode does not exceed the discharge start voltage, and a weak discharge is generated between the scan electrode and the sustain electrode. Can not be made.

  Therefore, it becomes difficult to adjust the wall charges of the scan electrode, the sustain electrode, and the data electrode to an amount necessary for the address discharge in the address period.

  Therefore, it is conceivable to increase the lamp voltage applied to the scan electrodes in order to generate a weak discharge after the above-described strong discharge. However, the cost of the drive circuit increases.

  An object of the present invention is to provide a plasma display apparatus and a driving method thereof capable of preventing a crosstalk generated between adjacent discharge cells and forming a desired amount of wall charges on a plurality of electrodes constituting the discharge cells. Is to provide.

  (1) A plasma display device according to one aspect of the present invention includes a plasma display panel having a plurality of discharge cells at intersections of scan electrodes, sustain electrodes, and a plurality of data electrodes, and one field period includes a plurality of subfields. A plasma display device driven by a subfield method, comprising: a scan electrode drive circuit for driving a scan electrode; a sustain electrode drive circuit for driving a sustain electrode; and a data electrode drive circuit for driving a data electrode; At least one of the subfields includes an initialization period in which wall charges of the plurality of discharge cells are adjusted to a state in which address discharge is possible, and the scan electrode driving circuit performs the initialization discharge in the initialization period. A ramp voltage changing from the first potential to the second potential is applied to the scan electrode, and the sustain electrode drive circuit A voltage that changes from the third potential to the fourth potential is applied to the sustain electrode so that the potential difference between the scan electrode and the sustain electrode becomes larger before the start of the change to the first potential. The electrode driving circuit operates in a fifth manner so that the potential difference between the scan electrode and each data electrode becomes small in synchronization with the change in the voltage of the sustain electrode before the start of the change of the scan electrode to the first potential. A voltage that changes from a potential to a sixth potential is applied to each data electrode.

  In this plasma display device, at least one subfield of the plurality of subfields includes an initialization period in which the wall charges of the plurality of discharge cells are adjusted to a state where address discharge is possible. In this initialization period, a ramp voltage that changes from the first potential to the second potential is applied to the scan electrodes by the scan electrode driving circuit.

  On the other hand, before the start of the change of the scan electrode to the first potential in the initialization period, the third potential is changed to the fourth potential so that the potential difference between the scan electrode and the sustain electrode becomes large. A voltage is applied to the sustain electrodes by the sustain electrode drive circuit. In addition, the potential difference between the scan electrode and each data electrode is small in synchronization with the change of the voltage applied to the sustain electrode before the start of the change of the scan electrode to the first potential during the initialization period. A voltage that changes from the fifth potential to the sixth potential is applied to the data electrode by the data electrode driving circuit.

  As described above, the potential difference between the sustain electrode and each data electrode increases before the start of the change of the scan electrode to the first potential, and a discharge occurs between the sustain electrode and each data electrode. . As a result, wall charges on the sustain electrode and each data electrode are erased or reduced.

  Further, when a weak erase discharge is performed at the end of the previous sustain period to prevent crosstalk, a large amount of wall charges are accumulated on the sustain electrode before the start of the initialization period. Even in such a case, since the wall charges are erased or reduced by the discharge between the sustain electrode and each data electrode, the change between the scan electrode and the sustain electrode at the start of the change to the first potential of the scan electrode. This prevents the occurrence of strong discharge. In this case, wall charges remain on the scan electrodes and the sustain electrodes.

  Thereafter, as described above, while the ramp voltage applied to the scan electrode changes from the first potential to the second potential, the voltage between the scan electrode and the sustain electrode is reliably set higher than the discharge start voltage. can do. Thereby, a weak initializing discharge is generated between the scan electrode and the sustain electrode. As a result, the wall charges of the plurality of discharge cells can be reliably adjusted to an amount necessary for address discharge.

  Further, since the voltage of each data electrode becomes the fifth potential so that the potential difference between the scan electrode and each data electrode becomes small, it is possible to prevent a strong discharge from occurring between the scan electrode and each data electrode. In addition, the occurrence of strong discharge between the scan electrode and the sustain electrode is prevented.

  As a result, the wall charges on the scan electrodes, the sustain electrodes, and the data electrodes are not erased by the strong discharge, and the wall charges of the plurality of discharge cells can be adjusted to values appropriate for the address discharge.

  (2) The data electrode driving circuit changes the voltage of each data electrode from the sixth potential to the fifth potential before the scan electrode starts to change to the first potential, and then The voltage of each data electrode may be returned to the sixth potential again after the start of the change to the first potential.

  In this case, ripples are prevented from occurring in the voltage of each data electrode when the ramp voltage changes. Thereby, an element with a low breakdown voltage can be used for the data electrode driving circuit.

  (3) The data electrode drive circuit may maintain the voltage of each data electrode at the sixth potential during the application of the ramp voltage. In this case, the voltage applied to each data electrode can be easily controlled.

  (4) The second potential is a positive potential higher than the first potential, the third potential is a positive potential higher than the fourth potential, and the sixth potential is the fifth potential It may be a positive potential higher than the potential.

  In this case, the ramp voltage applied to the scan electrode rises from the first potential to the second potential. In addition, the voltage applied to the sustain electrode falls from the third potential to the fourth potential before the start point of the change of the scan electrode to the first potential. Further, the voltage applied to each data electrode rises from the fifth potential to the sixth potential before the start of the change of the scan electrode to the first potential. Thus, since a positive voltage is applied to the scan electrode, the sustain electrode, and each data electrode, the configuration of the power supply circuit is not complicated.

  (5) The fourth potential and the sixth potential are set so that the first discharge is generated between the sustain electrode and each data electrode, and the ramp voltage is set to the first potential after the first discharge. The second discharge is set to occur between the scan electrode and the sustain electrode during the change from the first potential to the second potential, and the discharge current at the second discharge is higher than the discharge current at the first discharge. It may be small.

  In this case, since the discharge current at the time of the second discharge is smaller than the discharge current at the time of the first discharge, the wall charges accumulated on the scan electrodes and the wall charges accumulated on the sustain electrodes are erased. It is adjusted to an appropriate amount.

  (6) The scan electrode drive circuit applies a pulse voltage having a seventh potential to the scan electrode at the end of the sustain period preceding the initialization period, and the sustain electrode drive circuit discharges the discharge cell in which the sustain discharge has been performed. In order to reduce the wall charge, a voltage that changes from the fourth potential to the third potential may be applied to the sustain electrode during the period of the pulse voltage.

  In this case, at the end of the sustain period preceding the initialization period, it is possible to leave many wall charges on the scan electrode and the sustain electrode by a weak erasing discharge. Thereby, in the address period after the initialization period, the address discharge is weakened, and crosstalk generated between adjacent discharge cells can be prevented.

  (7) The scan electrode driving circuit scans the ramp pulse voltage having the seventh potential at the end of the sustain period before the initialization period in order to reduce the wall charge of the discharge cell that has performed the sustain discharge. When applied to the electrode, the leading edge of the ramp pulse voltage changes more slowly than the trailing edge, and the sustain electrode driving circuit may hold the sustain electrode at the third potential during the ramp pulse voltage.

  In this case, since the leading edge of the ramp pulse voltage gradually changes at the end of the sustain period preceding the initialization period, a large amount of wall charges may remain on the scan electrode and the sustain electrode due to the weak erase discharge. It becomes possible. Thereby, in the address period after the initialization period, the address discharge is weakened, and crosstalk generated between adjacent discharge cells can be prevented.

  (8) A driving method of a plasma display device according to another aspect of the present invention includes a plasma display panel having a plurality of discharge cells at intersections of scan electrodes, sustain electrodes, and a plurality of data electrodes. A driving method of a plasma display device driven by a subfield method including a subfield, the method comprising: driving a scan electrode, driving a sustain electrode, and driving a data electrode, and a plurality of subfields At least one of the subfields includes an initialization period in which wall charges of the plurality of discharge cells are adjusted to a state in which address discharge is possible, and the step of driving the scan electrode is performed for the initialization discharge in the initialization period. Applying a ramp voltage varying from the first potential to the second potential to the scan electrode, and maintaining The step of driving the pole changes from the third potential to the fourth potential so that the potential difference between the scan electrode and the sustain electrode is increased before the start of the change of the scan electrode to the first potential. A step of applying a voltage to the sustain electrode, and the step of driving the data electrode includes the scan electrode and each data in synchronization with a change in the voltage of the sustain electrode before the start of the change of the scan electrode to the first potential. A step of applying a voltage that changes from the fifth potential to the sixth potential to each data electrode so that the potential difference between the electrodes may be reduced may be included.

  In this method for driving a plasma display device, at least one subfield of the plurality of subfields includes an initialization period in which the wall charges of the plurality of discharge cells are adjusted to a state in which address discharge is possible. In this initialization period, a ramp voltage that changes from the first potential to the second potential is applied to the scan electrodes.

  On the other hand, before the start of the change of the scan electrode to the first potential in the initialization period, the third potential is changed to the fourth potential so that the potential difference between the scan electrode and the sustain electrode becomes large. A voltage is applied to the sustain electrode. In addition, the potential difference between the scan electrode and each data electrode is small in synchronization with the change of the voltage applied to the sustain electrode before the start of the change of the scan electrode to the first potential during the initialization period. A voltage that changes from the fifth potential to the sixth potential is applied to the data electrode.

  As described above, the potential difference between the sustain electrode and each data electrode increases before the start of the change of the scan electrode to the first potential, and a discharge occurs between the sustain electrode and each data electrode. . As a result, wall charges on the sustain electrode and each data electrode are erased or reduced.

  Further, when a weak erase discharge is performed at the end of the previous sustain period to prevent crosstalk, a large amount of wall charges are accumulated on the sustain electrode before the start of the initialization period. Even in such a case, since the wall charges are erased or reduced by the discharge between the sustain electrode and each data electrode, the change between the scan electrode and the sustain electrode is started at the start of the change of the scan electrode to the first potential. This prevents the occurrence of strong discharge. In this case, wall charges remain on the scan electrodes and the sustain electrodes.

  Thereafter, as described above, while the ramp voltage applied to the scan electrode changes from the first potential to the second potential, the voltage between the scan electrode and the sustain electrode is reliably set higher than the discharge start voltage. can do. Thereby, a weak initializing discharge is generated between the scan electrode and the sustain electrode. As a result, the wall charges of the plurality of discharge cells can be reliably adjusted to an amount necessary for address discharge.

  Further, since the voltage of each data electrode becomes the fifth potential so that the potential difference between the scan electrode and each data electrode becomes small, it is possible to prevent a strong discharge from occurring between the scan electrode and each data electrode. In addition, the occurrence of strong discharge between the scan electrode and the sustain electrode is prevented.

  As a result, the wall charges on the scan electrodes, the sustain electrodes, and the data electrodes are not erased by the strong discharge, and the wall charges of the plurality of discharge cells can be adjusted to values appropriate for the address discharge.

  According to the present invention, it is possible to prevent crosstalk generated between adjacent discharge cells and to form a desired amount of wall charges on a plurality of electrodes constituting the discharge cells.

FIG. 1 is an exploded perspective view showing a part of a plasma display panel in a plasma display apparatus according to an embodiment of the present invention. FIG. 2 is an electrode array diagram of a panel according to an embodiment of the present invention. FIG. 3 is a circuit block diagram of a plasma display device according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a driving waveform applied to each electrode of the plasma display device according to the embodiment of the present invention. 5 is a partially enlarged view of the drive waveform of FIG. FIG. 6 is an enlarged view showing another example of a driving waveform applied to each electrode of the plasma display device according to one embodiment of the present invention. FIG. 7 is a view showing still another example of the driving waveform applied to each electrode of the plasma display device according to the embodiment of the present invention. FIG. 8 is a partially enlarged view of the drive waveform of FIG. FIG. 9 is a circuit diagram showing the configuration of the scan electrode driving circuit of FIG. FIG. 10 is a timing chart of control signals supplied to the scan electrode drive circuit of FIG. 9 during the initialization period of the first SF of FIG. 11 is a circuit diagram showing the configuration of the sustain electrode driving circuit of FIG. FIG. 12 is a timing chart of the control signal applied to the sustain electrode driving circuit before and after the initializing period of the first SF of FIG. FIG. 13 is a circuit diagram showing the configuration of the data electrode driving circuit of FIG. FIG. 14 is a timing chart of control signals supplied to the data electrode driving circuit during the initialization period of the first SF of FIG. 15 is a circuit diagram showing another configuration of the scan electrode driving circuit of FIG. FIG. 16 is a timing chart of control signals supplied to the scan electrode driving circuit of FIG. 15 during the initialization period of the first SF of FIG. FIG. 17 is a circuit diagram showing still another configuration of the scan electrode driving circuit of FIG. FIG. 18 is a timing chart of control signals supplied to the scan electrode driving circuit of FIG. 17 during the initialization period of the first SF of FIG. FIG. 19 shows an example of a panel drive voltage waveform using the panel drive method of Patent Document 2. FIG. 20 shows an example of a panel drive waveform for preventing crosstalk between adjacent discharge cells.

  Hereinafter, a plasma display device and a driving method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Panel FIG. 1 is an exploded perspective view showing a part of a plasma display panel in a plasma display apparatus according to an embodiment of the present invention.

  A plasma display panel (hereinafter abbreviated as “panel”) 10 includes a glass front substrate 21 and a rear substrate 31 that are arranged to face each other. A discharge space is formed between the front substrate 21 and the rear substrate 31. A plurality of pairs of scan electrodes 22 and sustain electrodes 23 are formed in parallel with each other on the front substrate 21. Each pair of scan electrode 22 and sustain electrode 23 constitutes a display electrode. A dielectric layer 24 is formed so as to cover the scan electrode 22 and the sustain electrode 23, and a protective layer 25 is formed on the dielectric layer 24.

  A plurality of data electrodes 32 covered with an insulator layer 33 are provided on the back substrate 31, and a grid-like partition wall 34 is provided on the insulator layer 33. A phosphor layer 35 is provided on the surface of the insulator layer 33 and the side surfaces of the partition walls 34. The front substrate 21 and the rear substrate 31 are arranged to face each other so that the plurality of pairs of scan electrodes 22 and sustain electrodes 23 and the plurality of data electrodes 32 intersect vertically, and between the front substrate 21 and the rear substrate 31. A discharge space is formed. In the discharge space, for example, a mixed gas of neon and xenon is enclosed as a discharge gas. Note that the structure of the panel is not limited to that described above, and for example, a structure including a stripe-shaped partition may be used.

  FIG. 2 is an electrode array diagram of the panel according to the embodiment of the present invention. N scan electrodes SC1 to SCn (scan electrode 22 in FIG. 1) and n sustain electrodes SU1 to SUn (sustain electrode 23 in FIG. 1) are arranged along the row direction, and m scan electrodes are arranged along the column direction. Data electrodes D1 to Dm (data electrode 32 in FIG. 1) are arranged. n and m are each a natural number of 2 or more. A discharge cell DC is formed at a portion where one pair of scan electrode SCi (i = 1 to n) and sustain electrode SUi (i = 1 to n) intersects with one data electrode Dj (j = 1 to m). Has been. Thereby, m × n discharge cells are formed in the discharge space.

(2) Configuration of Plasma Display Device FIG. 3 is a circuit block diagram of a plasma display device according to an embodiment of the present invention.

  The plasma display device includes a panel 10, an image signal processing circuit 51, a data electrode drive circuit 52, a scan electrode drive circuit 53, a sustain electrode drive circuit 54, a timing generation circuit 55, and a power supply circuit (not shown).

  The image signal processing circuit 51 converts the image signal sig into image data corresponding to the number of pixels of the panel 10, divides the image data of each pixel into a plurality of bits corresponding to a plurality of subfields, and drives these data electrodes Output to the circuit 52.

  The data electrode drive circuit 52 converts the image data for each subfield into signals corresponding to the data electrodes D1 to Dm, and drives the data electrodes D1 to Dm based on the signals.

  The timing generation circuit 55 generates a timing signal based on the horizontal synchronization signal H and the vertical synchronization signal V, and outputs these timing signals to respective drive circuit blocks (image signal processing circuit 51, data electrode drive circuit 52, scan electrode drive). Circuit 53 and sustain electrode drive circuit 54).

  Scan electrode drive circuit 53 supplies a drive waveform to scan electrodes SC1 to SCn based on the timing signal, and sustain electrode drive circuit 54 supplies a drive waveform to sustain electrodes SU1 to SUn based on the timing signal.

(3) Panel Driving Method A panel driving method in this embodiment will be described. FIG. 4 is a diagram illustrating an example of a driving waveform applied to each electrode of the plasma display device according to the embodiment of the present invention. FIG. 5 is a partially enlarged view of the drive waveform of FIG.

  4 and 5, the drive waveform applied to one scan electrode among scan electrodes SC1 to SCn, one drive waveform among sustain electrodes SU1 to SUn, and one of data electrodes D1 to Dn. A drive waveform is shown.

  In the present embodiment, each field is divided into a plurality of subfields. In the present embodiment, one field is divided into 10 subfields (hereinafter abbreviated as first SF, second SF,..., And 10th SF) on the time axis. A pseudo subfield (hereinafter abbreviated as pseudo SF) is provided in a period from the 10th SF of each field to the next field.

  FIG. 4 shows from the sustaining period of the 10th SF of the previous field to the initialization period of the 3rd SF of the next field. FIG. 5 shows the sustain period from the tenth SF of FIG. 4 to the first SF write period of the next field.

  In the following description, a voltage generated by wall charges accumulated on a dielectric layer or a phosphor layer covering the electrode is referred to as a wall voltage on the electrode.

  As shown in FIGS. 4 and 5, the voltage of the sustain electrode SUi is raised to Ve1 after a predetermined time (phase difference TR) from the rise of the voltage of the scan electrode SCi to Vs at the end of the tenth SF of the previous field. Thereby, an erasing discharge is generated between scan electrode SCi and sustain electrode SUi, and the positive wall charge accumulated in scan electrode SCi and the negative wall charge accumulated in sustain electrode SUi are reduced. In the present embodiment, the phase difference TR is set small so that the erasing discharge is weakened. Generally, the phase difference TR for erasing discharge as described above is about 450 nsec. In contrast, in this example, the phase difference TR is set to 150 nsec, for example.

  Thus, by setting the phase difference TR to be small, the erasing discharge between the scan electrode SCi and the sustain electrode SUi becomes weak. As a result, a large amount of positive wall charges remains on the scan electrode SCi, and a large amount of negative wall charges remains on the sustain electrode SUi. At this time, positive wall charges are accumulated on the data electrode Dj.

  In the first half of the pseudo SF, the sustain electrode SUi is held at the voltage Ve1, the data electrode Dj is held at the ground potential (reference voltage), and the ramp voltage is applied to the scan electrode SCi. The ramp voltage gradually decreases from the positive voltage Vi5 slightly higher than the ground potential toward the negative voltage Vi4 that is equal to or lower than the discharge start voltage.

  Thereby, a weak discharge is generated between scan electrode SCi and data electrode Dj and between scan electrode SCi and sustain electrode SUi. As a result, the positive wall charge on the scan electrode SCi is slightly increased, and the negative wall charge on the sustain electrode SUi is slightly increased. Further, positive wall charges are accumulated on the data electrode Dj. In this way, the wall charges of all the discharge cells DC are adjusted almost uniformly.

  In the second half of the pseudo SF, the scan electrode SCi is held at the ground potential.

  In this way, at the end of the pseudo SF, a large amount of positive wall charge is accumulated in the scan electrode SCi, and a large amount of negative wall charge is accumulated in the sustain electrode SUi.

  After that, as shown in FIG. 5, at the time t1 immediately before the first SF of the next field, the voltage of the sustain electrode SUi is lowered from Ve1 to the ground potential. Then, at the start time t2 of the initialization period of the first SF, a pulsed positive voltage Vd is applied to the data electrode Dj.

  Immediately before time t2, a large amount of negative wall charges is accumulated on the sustain electrode SUi, and positive wall charges are accumulated on the data electrode Dj. When the voltage of data electrode Dj rises to Vd, the voltage between sustain electrode SUi and data electrode Dj becomes a value obtained by adding the wall voltage on data electrode Dj and the wall voltage on sustain electrode SUi to voltage Vd. . As a result, when the voltage between sustain electrode SUi and data electrode Dj exceeds the discharge start voltage, strong discharge is generated between sustain electrode SUi and data electrode Dj.

  Due to this strong discharge, the negative wall charges on the sustain electrodes SUi are erased, and zero or a small amount of positive wall charges are accumulated on the sustain electrodes SUi. Further, the wall charges on the data electrode Dj are erased, and zero or a small amount of negative wall charges are accumulated on the data electrode Dj. At this time, the positive wall charges on the scan electrode SCi are also slightly erased.

  Thereafter, the voltage of the scan electrode SCi is raised at time t3, and then the scan electrode SCi is held at the positive voltage Vi1 at time t4. At this time t4, the voltage of the data electrode Dj is raised to Vd. At this time, since zero or a small amount of positive wall voltage is accumulated on sustain electrode SUi, strong discharge does not occur between scan electrode SCi and sustain electrode SUi.

  A ramp voltage is applied to scan electrode SCi at time t4. The ramp voltage gradually increases from the positive voltage Vi1 that is equal to or lower than the discharge start voltage to the positive voltage Vi2 that exceeds the discharge start voltage from time t5 to time t6. At this time, since the data electrode Dj is held at the voltage Vd, it is possible to prevent a strong discharge from occurring between the scan electrode SCi and the data electrode Dj. Further, sustain electrode SUi is held at the ground potential.

  When the voltage between scan electrode SCi and sustain electrode SUi exceeds the discharge start voltage as the lamp voltage increases, a weak initializing discharge occurs between scan electrode SCi and sustain electrode SUi in all discharge cells DC. .

  Thereby, the positive wall charges accumulated on the scan electrode SCi are gradually erased, and the negative wall charges are accumulated on the scan electrode SCi. On the other hand, positive wall charges are accumulated on the sustain electrode SUi.

  At time t7, the voltage of scan electrode SCi falls, and at time t8, scan electrode SCi is held at voltage Vi3. At this time, a positive voltage Ve1 is applied to the sustain electrode SUi.

  At time t9, a negative ramp voltage is applied to scan electrode SCi. This ramp voltage drops from the positive voltage Vi3 to the negative voltage Vi4 from time t9 to time t10. At time t9, the voltage of the data electrode Dj is lowered and held at the ground potential.

  From time t9 to time t10, the voltage of the sustain electrode SUi is held at the positive voltage Ve1. Thus, when the voltage between scan electrode SCi and sustain electrode SUi exceeds the discharge start voltage as the lamp voltage decreases, weak initializing discharge occurs in all discharge cells DC.

  Thereby, the negative wall charges accumulated on scan electrode SCi are gradually erased from time t9 to time t10, and a small amount of negative wall charge remains on scan electrode SCi at time t10. On the other hand, from time point t9 to time point t10, the positive wall charges accumulated on sustain electrode SUi are gradually erased, and at time point t10, negative wall charges are accumulated on sustain electrode SUi. Further, positive wall charges are accumulated in the data electrode Dj from time t9 to time t10.

  At time t10, the voltage of scan electrode SCi is raised to the ground potential. Thereby, the initialization period ends, and the wall voltage on scan electrode SCi, the wall voltage on sustain electrode SUi, and the wall voltage on data electrode Dj are adjusted to values suitable for the write operation. Specifically, a small amount of negative wall charge is accumulated on scan electrode SCi, negative wall charge is accumulated on sustain electrode SUi, and positive wall charge is accumulated on data electrode Dj.

  As described above, in the initializing period of the first SF, the all-cell initializing operation for generating the initializing discharge in all the discharge cells DC is performed.

  Returning to FIG. 4, in the address period of the first SF, the voltage Ve2 is applied to the sustain electrode SUi, and the voltage of the scan electrode SCi is held at the ground potential. Next, a scan pulse having a negative voltage Va is applied to scan electrode SC1 in the first row, and data electrode Dk (k is any one of 1 to m) of the discharge cell that should emit light in the first row of data electrodes Dj. A write pulse having a positive voltage Vd.

  Then, the voltage at the intersection of the data electrode Dk and the scan electrode SC1 becomes a value obtained by adding the wall voltage on the data electrode Dk and the wall voltage on the scan electrode SC1 to the externally applied voltage (Vd−Va). Over voltage. Thereby, address discharge is generated between data electrode Dk and scan electrode SC1, and between sustain electrode SU1 and scan electrode SC1.

  Here, in the present embodiment, as described above, negative wall charges are accumulated in scan electrode SCi and sustain electrode SUi, and positive wall charges are accumulated in data electrode Dj at the start of the address period. . Therefore, the address discharge between sustain electrode SU1 and scan electrode SC1 is weakened.

  Thereby, even when the distance between adjacent discharge cells is set small in the panel of FIG. 1, it is possible to prevent crosstalk from occurring between adjacent discharge cells DC.

  Due to the address discharge, positive wall charges are accumulated on scan electrode SC1 of discharge cell DC, negative wall charges are accumulated on sustain electrode SU1, and negative wall charges are also accumulated on data electrode Dk. The

  In this manner, the address operation is performed in which the address discharge is generated in the discharge cells DC to emit light in the first row and the wall charges are accumulated on the respective electrodes. On the other hand, the voltage in the discharge cell DC at the intersection of the data electrode Dh (h ≠ k) to which the address pulse is not applied and the scan electrode SC1 does not exceed the discharge start voltage, so that address discharge does not occur.

  The address operation described above is sequentially performed from the discharge cell DC in the first row to the discharge cell in the nth row, and the address period ends.

  In the subsequent sustain period, sustain electrode SUi is returned to the ground potential, and sustain pulse voltage Vs having voltage Vs is applied to scan electrode SCi. At this time, in the discharge cell DC in which the address discharge is generated in the address period, the voltage between the scan electrode SCi and the sustain electrode SUi is the sustain pulse voltage Vs, the wall voltage on the scan electrode SCi, and the sustain electrode SUi. The wall voltage is added and exceeds the discharge start voltage.

  As a result, a sustain discharge occurs between scan electrode SCi and sustain electrode SUi, and discharge cell DC emits light. As a result, negative wall charges are accumulated on scan electrode SCi, positive wall charges are accumulated on sustain electrode SUi, and positive wall charges are accumulated on data electrode Dk. In the discharge cells DC in which no address discharge has occurred in the address period, no sustain discharge occurs, and the wall charge state at the end of the initialization period is maintained.

  Subsequently, scan electrode SCi is returned to the ground potential, and a sustain pulse having voltage Vs is applied to sustain electrode SUi. Then, in the discharge cell DC in which the sustain discharge has occurred, since the voltage between the sustain electrode SUi and the scan electrode SCi exceeds the discharge start voltage, the sustain discharge occurs again between the sustain electrode SUi and the scan electrode SCi, and the sustain cell is maintained. Negative wall charges are accumulated on the electrode SUi, and positive wall charges are accumulated on the scan electrode SCi.

  Thereafter, similarly, by applying a predetermined number of sustain pulses alternately to scan electrode SCi and sustain electrode SUi, sustain discharge is continuously performed in discharge cell DC in which the address discharge has occurred in the address period.

  Before the end of the sustain period, the voltage applied to the sustain electrode SUi is raised to Ve1 after a predetermined time (phase difference TR) after the voltage applied to the scan electrode SCi rises to Vs. As a result, similarly to the end of the tenth SF described with reference to FIG. 5, a weak erasing discharge occurs between the scan electrode SCi and the sustain electrode SUi.

  In the initialization period of the second SF, similarly to the pseudo SF described with reference to FIG. 5, the voltage of the sustain electrode SUi is held at Ve1, the data electrode Dj is held at the ground potential, and the positive voltage is applied to the scan electrode SCi. A ramp voltage that gently falls from Vi5 toward negative voltage Vi4 is applied. Then, a weak initializing discharge is generated in the discharge cell DC in which the sustain discharge has occurred in the sustain period of the previous subfield.

  Thereby, the wall voltage on scan electrode SCi and the wall voltage on sustain electrode SUi are weakened, and the wall voltage on data electrode Dk is also adjusted to a value suitable for the write operation.

  On the other hand, in the discharge cell DC in which the address discharge and the sustain discharge did not occur in the previous subfield, no discharge occurred, and the wall charge state at the end of the initialization period of the previous subfield was maintained. It is.

  As described above, in the initializing period of the second SF, the selective initializing operation for selectively generating the initializing discharge in the discharge cell DC in which the sustain discharge has occurred in the immediately preceding subfield is performed.

  In the second SF address period, as in the first SF address period, the address operation is sequentially performed from the discharge cell in the first row to the discharge cell in the nth row, and the address period ends. Since the operation in the subsequent sustain period is the same as the operation in the sustain period of the first SF except for the number of sustain pulses, description thereof is omitted.

  In the subsequent initialization period from the third SF to the tenth SF, the selective initialization operation is performed as in the initialization period of the second SF. In the address period from the third SF to the tenth SF, the address operation is performed by applying the voltage Ve2 to the sustain electrode SUi as in the second SF. In the sustain period from the third SF to the tenth SF, the same sustain operation as that of the first SF is performed except for the number of sustain pulses.

(4) Other examples of drive waveforms (4-a) Regarding wall charge adjustment Wall charges of scan electrode SCi and sustain electrode SUi before the start of pseudo SF are adjusted by applying the following drive waveforms to each electrode. You may go. FIG. 6 is an enlarged view showing another example of a driving waveform applied to each electrode of the plasma display device according to one embodiment of the present invention.

  As shown in FIG. 6, in this example, in order to perform weak erase discharge before selective initialization, the sustain electrode SUi and the data electrode Dj are held at the ground potential at the end of the tenth SF of the previous field. A ramp voltage is applied to the scan electrode SCi. This ramp voltage rises gradually from the ground potential toward the positive voltage Vs.

  Here, in the discharge cell DC in which the sustain discharge has occurred, positive wall charges are accumulated in the scan electrode SCi, and negative wall charges are accumulated in the sustain electrode SUi. Therefore, as described above, when the ramp voltage is applied to scan electrode SCi, in discharge cell DC in which the sustain discharge has occurred, the voltage between scan electrode SCi and sustain electrode SUi exceeds the discharge start voltage. Again, a weak erase discharge is generated between sustain electrode SUi and scan electrode SCi.

  As a result, the positive wall charges accumulated in scan electrode SCi and the negative wall charges accumulated in sustain electrode SUi are slightly reduced, so that a lot of positive wall charges remain in scan electrode SCi, and the negative wall charges in sustain electrode SUi. A lot of charge remains. At this time, positive wall charges are accumulated on the data electrode Dj.

  Thus, similarly to the example of FIGS. 4 and 5, the selective initialization operation is performed in the subsequent pseudo-SF, and the all-cell initialization operation is performed in the initialization period of the first SF in the next field, whereby the scan electrode SCi. The upper wall voltage, the wall voltage on the sustain electrode SUi, and the wall voltage on the data electrode Dj are adjusted to values suitable for the write operation.

(4-b) Regarding Setting of Initialization Period in Field In the example of FIG. 4, the initialization period is provided at the beginning of the first SF that is the first subfield of the field. Hereinafter, an example in which the initialization period is provided between predetermined subfields in the field will be described.

  FIG. 7 is a view showing still another example of the drive waveform applied to each electrode of the plasma display apparatus according to the embodiment of the present invention, and FIG. 8 is a partially enlarged view of the drive waveform of FIG. .

  The drive waveforms shown in FIGS. 7 and 8 will be described while referring to differences from the drive waveforms shown in FIGS. As shown in FIG. 7, in the driving waveform of this example, after the pseudo SF of the previous field, all cells are not initialized by the first SF of the next field.

  That is, the first SF does not have an initialization period, and the other subfields have an initialization period. In addition, after the erase operation is performed in the first SF, the all-cell initialization operation is performed in the initialization period of the second SF.

  FIG. 7 shows from the sustaining period of the 10th SF of the previous field to the initialization period of the 3rd SF of the next field.

  In the address period of the first SF, similarly to the address period described with reference to FIG. 4, the scan pulse having the negative voltage Va is applied to the sustain electrode SUi, and the address pulse having the positive voltage Vd is applied to the data electrode Dk. Apply.

  Thereby, address discharge is generated between data electrode Dk and scan electrode SC1, and between sustain electrode SU1 and scan electrode SC1. This address operation is sequentially performed from the discharge cell DC in the first row to the discharge cell in the nth row, and the address period ends.

  In the subsequent sustain period, similarly to the sustain period described with reference to FIG. 4, sustain electrode SUi is returned to the ground potential, and a sustain pulse having voltage Vs is applied to scan electrode SCi.

  Thereby, in the discharge cell DC in which the address discharge is generated in the address period, a sustain discharge occurs between the scan electrode SCi and the sustain electrode SUi, and the discharge cell DC emits light. Thereafter, similarly, by applying a predetermined number of sustain pulses alternately to scan electrode SCi and sustain electrode SUi, sustain discharge is continuously performed in discharge cell DC in which the address discharge has occurred in the address period.

  Here, as shown in FIG. 8, in the first SF, after the end of the sustain period, an erasing period is provided before the start of the second SF.

  In the erase period, similarly to the end of the sustain period of the 10th SF of the previous field described with reference to FIGS. 4 and 5, a predetermined time (set to a small value after the voltage of the scan electrode SCi is raised to Vs) ( After the phase difference TR), the voltage of the sustain electrode SUi is raised to Ve1.

  As a result, a weak erase discharge is generated between scan electrode SCi and sustain electrode SUi. Accordingly, a large amount of positive wall charges can be left in scan electrode SCi, and a large amount of negative wall charges can be left in sustain electrode SUi. In this state, the first SF ends.

  After that, as shown in FIG. 8, in the initialization period set at the beginning of the second SF, the all-cell initialization operation similar to the example of FIGS. 4 and 5 is performed. Thereafter, in the address period and the sustain period in the second SF, the address operation and the sustain operation similar to those in the examples of FIGS. 4 and 5 are performed.

  The third SF to the tenth SF following the second SF have an initialization period, an address period, and a sustain period, respectively, and a selective initialization operation is performed in these initialization periods.

  As described above, in the plasma display device according to the present embodiment, an initialization period for performing the all-cell initialization operation may be provided between predetermined subfields in the field.

(5) Circuit Configuration and Operation Control of Scan Electrode Drive Circuit 53 (5-a) Circuit Configuration FIG. 9 is a circuit diagram showing the configuration of scan electrode drive circuit 53 in FIG. In the following description, an example of a positive pulse that discharges when the drive voltage rises is shown, but a negative pulse that discharges when the drive voltage falls may be used.

  9 includes FETs (field effect transistors, hereinafter abbreviated as transistors) Q11 to Q22, recovery capacitors C11, capacitors C12 to C15, recovery coils L11 and L12, power supply terminals V11 to V14, and diodes. DD11 to DD14 are included.

  The transistor Q13 of the scan electrode driving circuit 53 is connected between the power supply terminal V11 and the node N13, and the control signal S13 is input to the gate. A voltage Vi1 is applied to the power supply terminal V11. The transistor Q14 is connected between the node N13 and the ground terminal, and a control signal S14 is input to a gate.

  The recovery capacitor C11 is connected between the node N11 and the ground terminal. Transistor Q11 and diode DD11 are connected in series between nodes N11 and N12a. Diode DD12 and transistor Q12 are connected in series between nodes N12b and N11. A control signal S11 is input to the gate of the transistor Q11, and a control signal S12 is input to the gate of the transistor Q12. The recovery coil L11 is connected between the node N12a and the node N13. The recovery coil L12 is connected between the node N12b and the node N13.

  Capacitor C12 is connected between nodes N14 and N13. Diode DD13 is connected between power supply terminal V12 and node N14. A voltage Vr is applied to the power supply terminal V12.

  The transistor Q15 is connected between the node N14 and the node N15, and a control signal S15 is input to a gate. Capacitor C13 is connected between node N14 and the gate of transistor Q15. The transistor Q16 is connected between the node N15 and the node N13, and a control signal S16 is input to a gate.

  The transistor Q17 is connected between the node N15 and the node N16, and a control signal S17 is input to a gate. The transistor Q18 is connected between the node N16 and the power supply terminal V13, and a control signal S18 is input to a gate. A voltage Vi4 is applied to the power supply terminal V13. Capacitor C14 is connected between node N16 and the gate of transistor Q18.

  Capacitor C15 is connected between nodes N16 and N17. Diode DD14 is connected between power supply terminal V14 and node N17. A voltage Vs is applied to the power supply terminal V14.

  The transistor Q19 is connected between the node N17 and the node N18, and a control signal S19 is input to a gate. The transistor Q20 is connected between the node N18 and the node N16, and a control signal S20 is input to a gate.

  The transistor Q21 is connected between the node N18 and the scan electrode SCi, and a control signal S21 is input to the gate. The transistor Q22 is connected between the node N16 and the scan electrode 12, and a control signal S22 is input to a gate.

  The control signals S11 to S22 are given as timing signals from the timing generation circuit 55 of FIG. 2 to the scan electrode driving circuit 53.

(5-b) Operation Control FIG. 10 is a timing chart of the control signals S11 to S22 supplied to the scan electrode drive circuit 53 of FIG. 9 during the initialization period of the first SF of FIG.

  At the start time t2 of the first SF, the control signals S11, S12, S13, S15, S18, S19, and S21 are each at a low level. Thereby, the transistors Q11, Q12, Q13, Q15, Q18, Q19, Q21 are turned off.

  Further, the control signals S14, S16, S17, S20, and S22 are each at a high level. Thereby, the transistors Q14, Q16, Q17, Q20, and Q22 are turned on. In this case, the voltage of the scan electrode SCi is the ground potential.

  At time t3, the control signal S11 becomes high level and the control signal S14 becomes low level. Thereby, the transistor Q11 is turned on and the transistor Q14 is turned off. Thereby, a current flows from the recovery capacitor C11 to the scan electrode SCi, and the voltage of the scan electrode SCi increases.

  Further, the control signal S11 becomes a low level immediately after the time point t3. Thereby, the transistor Q11 is turned off. At the same time, the control signal S13 is at a high level. Thereby, the transistor Q13 is turned on.

  In this case, the current flowing from the recovery capacitor C11 to the scan electrode SCi is interrupted, and the current flows from the power supply terminal V11 to the scan electrode SCi. As a result, the voltage of the scan electrode SCi rises and becomes Vi1 at time t4.

  Next, at time t5, the control signal S15 becomes high level and the control signal S16 becomes low level. Thereby, the transistor Q15 is turned on and the transistor Q16 is turned off.

  In this case, the current flowing from power supply terminal V11 to scan electrode SCi is interrupted, and the current flows from power supply terminal V12 to scan electrode SCi. At this time, since the voltage of the node N15 is held at Vi1, the voltage of the scan electrode SCi rises gently and becomes Vi2, that is, (Vi1 + Vr) at time t6.

  Next, at time t7, the control signal S15 becomes low level, and the control signal S16 becomes high level. Thereby, the transistor Q15 is turned off and the transistor Q16 is turned on. As a result, the voltage of the scan electrode SCi drops and becomes the voltage Vi1 (the above-mentioned voltage Vi3) of the power supply terminal V11 at time t8.

  Next, at time t9, the control signal S13 becomes low level, the control signal S17 becomes low level, and the control signal S18 becomes high level. Thereby, the transistor Q13 is turned off, the transistor Q17 is turned off, and the transistor Q18 is turned on. In this case, the voltage of the scan electrode SCi gradually decreases and becomes the voltage Vi4 of the power supply terminal V13 at time t10.

  At time t10, the control signal S19 becomes high level and the transistor Q19 is turned on. Thereby, the voltage Vs of the power supply terminal V14 is applied to the scan electrode SCi, so that the voltage of the scan electrode SCi becomes almost the ground potential.

  In the above configuration, a ramp waveform (not shown) that changes in a curve may be applied to the scan electrode SCi by adjusting the capacitance of the capacitor C13, for example.

(6) Circuit Configuration and Operation Control of Sustain Electrode Drive Circuit 54 (6-a) Circuit Configuration FIG. 11 is a circuit diagram showing the configuration of sustain electrode drive circuit 54 of FIG.

  Sustain electrode driving circuit 54 in FIG. 11 includes a sustain driver 540 and a voltage raising circuit 541.

  The sustain driver 540 of FIG. 11 includes n-channel FETs (field effect transistors, hereinafter abbreviated as transistors) Q101 to Q104, a recovery capacitor C101, a recovery coil L101, and diodes DD21 to DD24.

  The voltage raising circuit 541 includes n-channel FETs (field effect transistors, hereinafter abbreviated as transistors) Q105a, Q107, Q108, p-channel FETs (field effect transistors, abbreviated as transistors hereinafter) Q105b, a diode DD25, and a capacitor C102. Including.

  The transistor Q101 of the sustain driver 540 is connected between the power supply terminal V101 and the node N101, and the control signal S101 is input to the gate. A voltage Vs is applied to the power supply terminal V1.

  The transistor Q102 is connected between the node N101 and the ground terminal, and a control signal S102 is input to a gate. Node N101 is connected to sustain electrode SUi in FIG.

  The recovery capacitor C101 is connected between the node N103 and the ground terminal. Transistor Q103 and diode DD21 are connected in series between nodes N103 and N102. Diode DD22 and transistor Q104 are connected in series between nodes N102 and N103.

  The control signal S103 is input to the gate of the transistor Q103, and the control signal S104 is input to the gate of the transistor Q104. The recovery coil L101 is connected between the node N101 and the node N102. Diode DD23 is connected between node N102 and power supply terminal V101, and diode DD24 is connected between the ground terminal and node N102.

  The diode DD25 of the voltage raising circuit 541 is connected between the power supply terminal V111 and the node N104, and the voltage Ve1 is applied to the power supply terminal V111.

  Transistor Q105a and transistor Q105b are connected in series between nodes N104 and N101. Control signals S105a and S105b are input to the gates of transistors Q105a and Q105b, respectively. Capacitor C102 is connected between nodes N104 and N105.

  The transistor Q107 is connected between the node N105 and the ground terminal, and a control signal S107 is input to a gate. The transistor Q108 is connected between the power supply terminal V103 and the node N105, and a control signal S108 is input to a gate. A voltage VE2 is applied to the power supply terminal V103. The voltage VE2 satisfies the relationship VE2 = Ve2-Ve1, and is, for example, VE2 = 5 [V].

  The control signals S101 to S104, S105a, S105b, S107, and S108 are given as timing signals from the timing generation circuit 55 of FIG. 3 to the sustain electrode drive circuit 54.

(6-b) Operation Control FIG. 12 is a timing chart of the control signals S101 to S104, S105a, S105b, S107, and S108 supplied to the sustain electrode drive circuit 54 before and after the initializing period of the first SF of FIG. . The control signal S105b has a waveform that is inverted with respect to the waveform of the control signal S105a.

  First, at the time point t0 of the pseudo SF of the previous field, the control signals S101, S102, S103, S104, S105b, and S108 are each at a low level. Thereby, the transistors Q101, Q102, Q103, Q104, and Q108 are turned off, and the transistor Q105b is turned on. Also, the control signals S105a and S107 are each at a high level. Thereby, the transistors Q105a and Q107 are each turned on.

  In this case, a current flows from the power supply terminal V111 to the sustain electrode SUi through the node N104. Thereby, the voltage of the sustain electrode SUi is held at Ve1.

  Next, at the time t1 immediately before the end of the pseudo SF, that is, the time t1 immediately before the first SF of the next field, the control signal S104 becomes high level, the control signal S105a becomes low level, and the control signal S105b becomes high level. It has become.

  Thereby, the transistor Q104 is turned on and the transistors Q105a and Q105b are turned off. Thereby, a current flows from the sustain electrode SUi (node N101) to the recovery capacitor C101 through the recovery coil L101, the diode DD22, and the transistor Q104. At this time, the charge of the panel capacitance is recovered by the recovery capacitor C101. As a result, the voltage of sustain electrode SUi (node N101) drops.

  Further, immediately after the time point t1, the control signal S104 becomes a low level, and the control signal S102 becomes a high level. Thereby, the transistor Q104 is turned off and the transistor Q102 is turned on. Thereby, node N101 is grounded, and sustain electrode SUi is at the ground potential.

  The control signal S102 is at a high level from the start time t2 of the first SF of the next field to the time t8 when the voltage of the scan electrode SCi starts to decrease from Vi3 to the voltage Vi4. Thereby, sustain electrode SUi (node N101) is held at the ground potential.

  Here, at time t8, the control signal S102 becomes low level, the control signal S105a becomes high level, and the control signal S105b becomes low level. Thereby, the transistor Q102 is turned off, and the transistors Q105a and Q105b are turned on. Thereby, a current again flows from the power supply terminal V111 to the sustain electrode SUi through the node N104. Thereby, the voltage of the sustain electrode SUi is held at Ve1.

  Thereafter, after the initialization period has elapsed, at time t11 immediately after the start of the writing period, the control signal S107 becomes low level and the control signal S108 becomes high level. Thereby, the transistor Q107 is turned off and the transistor Q108 is turned on. Thereby, a current flows from power supply terminal V103 to node N105 through transistor Q108. As a result, the voltage at the node N105 rises to VE2. In this case, the voltage VE2 is added to the voltage Ve1 of the sustain electrode SUi. As a result, the voltage of sustain electrode SUi (node N101) rises to Ve2.

(7) Circuit Configuration and Operation Control of Data Electrode Drive Circuit 52 (7-a) Circuit Configuration FIG. 13 is a circuit diagram showing the configuration of data electrode drive circuit 52 in FIG.

  13 includes a plurality of p-channel FETs (field effect transistors, hereinafter abbreviated as transistors) Q211 to Q21m, and a plurality of n-channel FETs (field effect transistors, abbreviated as transistors hereinafter) Q221. Includes Q22m.

  A power supply terminal V201 is connected to the node N201. A voltage Vd is applied to the power supply terminal V201.

  Transistors Q211 to Q21m are connected between node N201 and nodes ND1 to NDm. Transistors Q221 to Q22m are connected between nodes ND1 to NDm and the ground terminal. The nodes ND1 to NDm are connected to the data electrode Dj in FIG.

  Control signals S201 to S20m are input to the gates of the plurality of transistors Q211 to Q21m, respectively. Control signals S201 to S20m are also input to the gates of the transistors Q221 to Q22m, respectively.

  The control signals S201 to S20m are given as timing signals from the timing generation circuit 55 in FIG. 2 to the data electrode driving circuit 52.

(7-b) Operation Control FIG. 14 is a timing chart of the control signals S201 to S20m supplied to the data electrode drive circuit 52 during the initialization period of the first SF of FIG.

  As shown in FIG. 14, at time t1 immediately before the first SF, the control signals S201 to S20m are both at the high level. Thereby, the transistors Q211 to Q21m are turned off and the transistors Q221 to 22m are turned on.

  In this case, nodes ND1 to NDm are connected to the ground terminal via transistors Q221 to 22m. Thereby, the data electrode Dj becomes the ground potential.

  Next, at the start time t2 of the first SF, both of the control signals S201 to S20m become low level. Thereby, the transistors Q211 to Q21m are turned on and the transistors Q221 to 22m are turned off.

  In this case, nodes ND1 to NDm are connected to node N201 via transistors Q211 to 21m. Thereby, a current flows from power supply terminal V201 to data electrode Dj through node N201 and transistors Q211 to Q21m. Thereby, the voltage of the data electrode Dj is held at Vd.

  Between time t2 and time t3, after a lapse of a predetermined time from time t2, the control signals S201 to S20m become high level. In this case, the data electrode Dj is at the ground potential as described above.

  After that, at time t4, both the control signals S201 to S20m again become low level. The control signals S201 to S20m are held at a low level from time t4 to time t9. Thereby, the voltage of the data electrode Dj is held at Vd.

  At time t9, the control signals S201 to S20m become high level. Control signals S201 to S20m are held at a high level from time t9 to the end of the initialization period. Thereby, the data electrode Dj is held at the ground potential.

(8) Other Circuit Configuration and Operation Control of Scan Electrode Drive Circuit 53 (8-a) Circuit Configuration In the present embodiment, scan electrode drive circuit 53 having the following configuration may be used. FIG. 15 is a circuit diagram showing another configuration of scan electrode drive circuit 53 of FIG. In the following description, an example of a positive pulse that discharges when the drive voltage rises is shown, but a negative pulse that discharges when the drive voltage falls may be used.

  The scan electrode drive circuit 53 of this example is different from the scan electrode drive circuit 53 of FIG. 9 in the following points.

  As shown in FIG. 15, in the scan electrode driving circuit 53 of this example, the transistor Q15 is connected between the node N14 and the node N18. As in the example of FIG. 9, a control signal S15 is input to the gate.

  The transistor Q14 is connected between the node N15 and the ground terminal, and a control signal S14 is input to the gate. The recovery coil L12 is connected between the node N15 and the node N12b.

(8-b) Operation Control FIG. 16 is a timing chart of the control signals S11 to S22 supplied to the scan electrode drive circuit 53 of FIG. 15 during the initialization period of the first SF of FIG.

  Control signals S11 to S22 given to scan electrode drive circuit 53 in FIG. 15 are the same as control signals S11 to S22 given to scan electrode drive circuit 53 in FIG. 9 except for the following points.

  According to the example of FIG. 16, the control signal S20 is maintained at the high level until the time point t4. In this case, the transistor Q20 is on. Immediately before time t4, the transistors Q11, Q12, Q14, Q15, Q18, Q19, and Q21 are turned off, and the transistors Q13, Q16, Q17, Q20, and Q22 are turned on. Therefore, a current flows from power supply terminal V11 to scan electrode SCi. Thereby, the voltage of scan electrode SCi rises to Vi1.

  At time t4, the control signal S20 becomes low level. Thereby, the transistor Q20 is turned off. At time t5, the control signals S15 and S21 are at a high level, and the control signals S16 and S22 are at a low level. Thereby, the transistors Q15 and Q21 are turned on, and the transistors Q16 and Q22 are turned off.

  In this case, the current flowing from power supply terminal V11 to scan electrode SCi is interrupted, and the current flows from power supply terminal V12 to scan electrode SCi. At this time, since the voltage of the node N16 is held at Vi1, the voltage of the scan electrode SCi gradually rises and becomes Vi2, that is, (Vi1 + Vr) at time t6.

  Next, at time t7, the control signal S15 becomes low level, and the control signals S16 and S19 become high level. Thereby, the transistor Q15 is turned off and the transistors Q16 and Q19 are turned on. In this case, the current flowing from power supply terminal V12 to scan electrode SCi is interrupted, and the current flows from power supply terminal V14 to scan electrode SCi. Thereby, the voltage of scan electrode SCi falls. At this time, since the voltage of the node N16 is held at Vi1, the voltage of the scan electrode SCi is held at (Vi1 + Vs) at time t7a.

  Next, at time t7b, the control signals S19 and S21 become low level, and the control signals S20 and S22 become high level. Thereby, the transistors Q19 and Q21 are turned off, and the transistors Q20 and Q22 are turned on. In this case, the current flowing from power supply terminal V14 to scan electrode SCi is interrupted, and the current flows from power supply terminal V11 to scan electrode SCi. Thereby, the voltage of scan electrode SCi drops to Vi1 at time t8.

  Next, at time t9, the control signals S13 and S17 become low level, and the control signal S18 becomes high level. Thereby, the transistors Q13 and Q17 are turned off and the transistor Q18 is turned on. In this case, the voltage of the scan electrode SCi gradually decreases and becomes the voltage Vi4 of the power supply terminal V13 at time t10.

  At time t10, the control signals S19 and S21 become high level, and the control signals S20 and S22 become low level. Thereby, the transistors Q19 and Q21 are turned on, and the transistors Q20 and Q22 are turned off. As a result, the voltage of scan electrode SCi becomes substantially the ground potential.

(9) Still Another Circuit Configuration and Operation Control of Scan Electrode Drive Circuit 53 (9-a) Circuit Configuration FIG. 17 is a circuit diagram showing still another configuration of scan electrode drive circuit 53 of FIG. In the following description, an example of a positive pulse that discharges when the drive voltage rises is shown, but a negative pulse that discharges when the drive voltage falls may be used. The scan electrode drive circuit 53 of this example is different from the scan electrode drive circuit 53 of FIG. 9 in the following points.

  As shown in FIG. 17, in scan electrode drive circuit 53 of this example, transistors Q19 and Q20 and capacitor C12 provided in scan electrode drive circuit 53 of FIG. 9 are not provided.

  The transistor Q21 is connected between the node N17 and the scan electrode SCi, and a control signal S21 is input to the gate. The transistor Q22 is connected between the node N16 and the scan electrode SCi, and a control signal S22 is input to the gate.

  The recovery coil L12 is connected between the node N15 and the node N12b. A voltage Vr ′ is applied to the power supply terminal V12 instead of the voltage Vr. The voltage Vr ′ is obtained by adding the voltage (Vi1−Vs) to the voltage Vr.

(9-b) Operation Control FIG. 18 is a timing chart of the control signals S11 to S18, S21, and S22 supplied to the scan electrode drive circuit 53 of FIG. 17 during the initialization period of the first SF of FIG.

  As shown in FIG. 18, in the scan electrode drive circuit 53 of FIG. 17, the drive waveform in the initialization period applied to the scan electrode SCi is slightly different from the drive waveform of FIG. First, the drive waveform applied to the scan electrode SCi of this example will be described.

  According to the drive waveform of FIG. 18, after the start of the initialization period, the voltage applied to the scan electrode SCi from time t3 to time t4 rises to Vs and is held.

  Subsequently, from time t5 to time t6, a ramp voltage that gradually rises from the voltage Vs by the voltage Vr ′ is applied to the scan electrode SCi. From time t6 to time t7, the voltage applied to the scan electrode SCi is held at (Vs + Vr ′).

  From time t7 to time t7a, the voltage applied to scan electrode SCi drops by voltage Vr 'and is held at (Vs + Vi1). Thereafter, from time t7b to time t8, the voltage applied to scan electrode SCi drops by voltage Vs and is held at Vi1.

  Next, from time t9 to time t10, a ramp voltage that decreases from voltage Vi1 to negative voltage Vi4 is applied to scan electrode SCi. Finally, at time 10, the voltage of the scan electrode SCi is raised from Vi4 to almost the ground potential and held. In this state, the initialization period ends.

  As described above, the following control signals S11 to S18, S21, and S22 are applied to the scan electrode drive circuit 53 of FIG. 17 in order to obtain the drive waveform applied to the scan electrode SCi.

  At the start time t2 of the first SF, the control signals S11, S12, S13, S15, S18, S19, and S21 are each at a low level. Thereby, the transistors Q11, Q12, Q13, Q15, Q18, and Q21 are turned off.

  Further, the control signals S14, S16, S17, and S22 are each at a high level. Thereby, the transistors Q14, Q16, Q17, and Q22 are turned on. In this case, scan electrode SCi is held at the ground potential.

  At time t3, the control signal S21 becomes high level, and the control signals S14 and S22 become low level. Thereby, the transistor Q21 is turned on and the transistors Q14 and Q22 are turned off. Thereby, the voltage of scan electrode SCi rises to Vs.

  At time t5, the control signal S15 becomes high level, and the control signal S16 becomes low level. Thereby, the transistor Q15 is turned on and the transistor Q16 is turned off. As a result, the voltage of the scan electrode SCi gradually increases from Vs by the voltage Vr ′, and reaches (Vs + Vr ′) at time t6. At time t6, the control signal S13 becomes high level. Thereby, the transistor Q13 is turned on. From time t5 to time t6, the voltage of the scan electrode SCi is held at (Vs + Vr ′).

  Next, at time t7, the control signal S15 becomes low level, and the control signal S16 becomes high level. Thereby, the transistor Q15 is turned off and the transistor Q16 is turned on. As a result, the voltage of the scan electrode SCi drops by Vr ′ and becomes (Vs + Vi1) at time t7a. From time t7a to time t7b, the voltage of scan electrode SCi is held at (Vs + Vi1).

  At time t7b, the control signal S21 becomes low level, and the control signal S22 becomes high level. Thereby, the transistor Q21 is turned off and the transistor Q22 is turned on. In this case, the voltage of the scan electrode SCi drops by Vs and becomes Vi1 at time t8. From time t8 to time t9, the voltage of scan electrode SCi is held at Vi1.

  At time t9, the control signals S13 and S17 become low level, and the control signal S18 becomes high level. Thereby, the transistors Q13 and Q17 are turned off and the transistor Q18 is turned on. In this case, the voltage of the scan electrode SCi gradually decreases and becomes the voltage Vi4 of the power supply terminal V13 at time t10.

  At time t10, the control signal S21 becomes high level and the transistor Q21 is turned on. Thereby, the voltage Vs of the power supply terminal V14 is applied to the scan electrode SCi, so that the voltage of the scan electrode SCi becomes almost the ground potential.

  In the above configuration, a ramp waveform (not shown) that changes in a curve may be applied to the scan electrode SCi by adjusting the capacitance of the capacitor C13, for example.

(10) Effect In the plasma display device according to the present embodiment, the time t3 (FIGS. 5, 6, and 8) when the scan electrode SCi rises to the positive voltage Vi1 in the initialization period in which the all-cell initialization operation is performed. ), A positive voltage Vd is applied to the data electrode Dj. As a result, a strong discharge is generated between sustain electrode SUi and data electrode Dj.

  Therefore, even when a lot of negative wall charges remain on the sustain electrode SUi due to the weak erasing discharge before the initialization of all the cells, the voltage between the scan electrode SCi and the sustain electrode SUi is applied when the ramp voltage is applied to the scan electrode SCi. Generation of strong discharge is prevented.

  As a result, an appropriate amount of wall charges remains on scan electrode SCi, so that the voltage between scan electrode SCi and sustain electrode SUi surely exceeds the discharge start voltage as the ramp voltage increases. As a result, a weak initializing discharge is generated between scan electrode SCi and sustain electrode SUi in the initializing period, and the wall charges on each electrode SCi, SUi are reliably adjusted to a desired amount.

  Further, since the data electrode Dj is held at the voltage Vd while the ramp voltage rises slowly, it is possible to prevent a strong discharge from occurring between the scan electrode SCi and the data electrode Dj.

  Further, the wall charge on scan electrode SCi and the wall charge on sustain electrode SUi are reduced by a weak erasing discharge between scan electrode SCi and sustain electrode SUi before the start of the initialization period. Accordingly, a large amount of positive wall charges can be left in scan electrode SCi, and a large amount of negative wall charges can be left in sustain electrode SUi. Therefore, in the address period after the initialization period, address discharge between scan electrode SCi and data electrode Di and between sustain electrode SUi and scan electrode SCi is weakened. As a result, even when the distance between adjacent discharge cells DC is small, it is possible to prevent crosstalk from occurring between adjacent discharge cells DC.

(11) Others (11-a)
For example, as shown in FIG. 5, in this plasma display device, a pulsed positive voltage Vd is applied to the data electrode Dj at the start time t2 of the initialization period. This is because the data electrode Dj is held at the ground potential when the ramp voltage rising from Vi1 to Vi2 is applied to the scan electrode SCi at the time point t3. This prevents the occurrence of ripples when the lamp voltage rises. Thereby, an IC (integrated circuit) having a low withstand voltage can be used for the plasma display device.

  Therefore, when the withstand voltage of an IC (integrated circuit) constituting the plasma display device is high, the positive voltage Vd applied to the data electrode Dj may not be pulsed. That is, the positive voltage Vd may be continuously applied to the data electrode Dj while the ramp voltage is applied to the scan electrode SCi (for example, from the time t2 to the time t9).

(11-b)
In the above embodiment, in the data electrode drive circuit 52, the scan electrode drive circuit 53, and the sustain electrode drive circuit 54, n-channel FETs and p-channel FETs are used as switching elements, but the switching elements are not limited to these. .

  For example, in each of the above circuits, a p-channel FET or IGBT (insulated gate bipolar transistor) may be used instead of the n-channel FET, or an n-channel FET or IGBT (insulated gate bipolar) instead of the p-channel FET. Transistor) or the like may be used.

(12) Correspondence between each constituent element of claim and each element of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each element of the embodiment will be described. It is not limited to.

  In the above embodiment, the voltage Vi1 and the voltage Vs in FIG. 18 are examples of the first potential, the voltage Vi2 and the voltage (Vs + Vr ′) in FIG. 18 are examples of the second potential, and the voltage Ve1 is the third potential. , The ground potential is an example of the fourth potential, the ground potential is an example of the fifth potential, the voltage Vd is an example of the sixth potential, and the voltage Vs is the seventh potential. 5, FIG. 6, and FIG. 8 is an example of the time point when the change of the scan electrode to the first potential starts.

  The present invention can be used in a display device that displays various images.

  The present invention relates to a plasma display device that selectively discharges a plurality of discharge cells to display an image and a driving method thereof.

(Plasma display panel structure)
A typical AC surface discharge type panel as a plasma display panel (hereinafter abbreviated as “panel”) includes a large number of discharge cells between a front plate and a back plate arranged to face each other.

  The front plate includes a front glass substrate, a plurality of display electrodes, a dielectric layer, and a protective layer. Each display electrode includes a pair of scan electrodes and sustain electrodes. The plurality of display electrodes are formed in parallel to each other on the front glass substrate, and a dielectric layer and a protective layer are formed so as to cover the display electrodes.

  The back plate includes a back glass substrate, a plurality of data electrodes, a dielectric layer, a plurality of barrier ribs, and a phosphor layer. A plurality of data electrodes are formed in parallel on the rear glass substrate, and a dielectric layer is formed so as to cover them. A plurality of barrier ribs are formed on the dielectric layer in parallel with the data electrodes, and R (red), G (green), and B (blue) phosphor layers are formed on the surface of the dielectric layer and the side surfaces of the barrier ribs. Has been.

  Then, the front plate and the back plate are arranged opposite to each other so that the display electrode and the data electrode are three-dimensionally crossed and sealed, and a discharge gas is sealed in the internal discharge space. A discharge cell is formed at a portion where the display electrode and the data electrode face each other.

  In the panel having such a configuration, ultraviolet rays are generated by gas discharge in each discharge cell, and the R, G, and B phosphors are excited by the ultraviolet rays to emit light. Thereby, color display is performed.

  The subfield method is used as a method for driving the panel. In the subfield method, one field period is divided into a plurality of subfields, and gradation display is performed by causing each discharge cell to emit light or not emit light in each subfield. Each subfield has an initialization period, an address period, and a sustain period.

(Conventional panel driving method 1)
In the initialization period, weak discharge (initialization discharge) is performed in each discharge cell, and wall charges necessary for the subsequent address operation are formed. In addition, the initialization period has a function of reducing discharge delay and generating priming for stably generating address discharge. Here, priming refers to excited particles that serve as an initiator for discharge.

  In the address period, scan pulses are sequentially applied to the scan electrodes, and address pulses corresponding to image signals to be displayed on the data electrodes are applied. Thereby, address discharge is selectively generated between the scan electrode and the data electrode, and selective wall charge formation is performed.

  In the subsequent sustain period, a predetermined number of sustain pulses corresponding to the luminance to be displayed is applied between the scan electrode and the sustain electrode. As a result, a discharge occurs selectively in the discharge cell in which the wall charge is formed by the address discharge, and the discharge cell emits light.

  Here, in the initialization period, in order to generate a weak discharge in each discharge cell, the voltage applied to each of the scan electrode, the sustain electrode, and the data electrode is adjusted.

  Specifically, in the first half of the initialization period (hereinafter referred to as the rising period), a ramp voltage that rises slowly is applied to the scan electrode while the voltage of the data electrode is held at the ground potential (reference voltage). . Thus, a weak discharge is generated between the scan electrode and the data electrode and between the sustain electrode and the data electrode during the rising period.

  In the second half of the initialization period (hereinafter referred to as a falling period), a ramp voltage that gradually decreases is applied to the scan electrode while the voltage of the data electrode is held at the ground potential. Thus, a weak discharge is generated between the scan electrode and the data electrode and between the sustain electrode and the data electrode during the descending period.

  As described above, for example, Patent Document 1 discloses a panel driving method in which a ramp voltage or a voltage that increases or decreases stepwise is applied to the scan electrode during the initialization period. As a result, the wall charges accumulated in the scan electrode and the sustain electrode are erased, and the wall charges necessary for the write operation are accumulated in each of the scan electrode, the sustain electrode and the data electrode.

  However, in practice, a strong discharge may occur between the scan electrode and the data electrode during the rising period. In this case, a strong discharge is generated between the scan electrode and the sustain electrode, a large amount of wall charges and a large amount of priming are generated in the discharge cell, and a strong discharge is easily generated even during the descending period.

  When a strong discharge is generated during the initialization period, wall charges accumulated in the scan electrode, the sustain electrode, and the data electrode are erased. Therefore, an appropriate amount of wall charges necessary for address discharge cannot be formed on each electrode.

  In view of this, Patent Document 2 discloses a panel driving method that prevents the occurrence of strong discharge during the initialization period.

(Conventional panel driving method 2)
FIG. 19 is an example of a panel drive voltage waveform (hereinafter referred to as a drive waveform) using the panel drive method of Patent Document 2. FIG. 19 shows waveforms of drive voltages applied to each of the scan electrode, the sustain electrode, and the data electrode during the sustain period, the initialization period, and the address period.

  As shown in FIG. 19, the data electrode is kept at a voltage Vd higher than the ground potential during the rising period of the initialization period.

  In this case, the voltage between the scan electrode and the data electrode is smaller than when the data electrode is held at the ground potential. Accordingly, the voltage between the scan electrode and the sustain electrode exceeds the discharge start voltage before the voltage between the scan electrode and the data electrode.

  Thus, during the rising period, priming occurs due to the weak discharge that occurs between the scan electrode and the sustain electrode. Thereafter, a weak discharge is generated between the scan electrode and the data electrode, so that wall charges necessary for an address operation are formed on each of the scan electrode, the sustain electrode, and the data electrode.

  For example, at the start of the address period of FIG. 19, negative wall charges are accumulated on the scan electrodes and positive wall charges are accumulated on the data electrodes. As a result, the address discharge in the address period is stabilized.

JP 2003-15599 A JP 2006-18298 A

  By the way, in recent years, the number of discharge cells (increase in the number of pixels) is increased and the distance between adjacent discharge cells is reduced as the screen is enlarged and the definition is increased. As a result, as will be described below, crosstalk is likely to occur between adjacent discharge cells.

  As shown in FIG. 19, the voltage of the sustain electrode is raised after a predetermined time (phase difference TR) since the voltage of the scan electrode is raised to Vcl at the end of the previous subfield. Thereby, an erasing discharge is generated between the scan electrode and the sustain electrode, and the positive wall charge accumulated in the scan electrode and the negative wall charge accumulated in the sustain electrode are erased or reduced.

  Next, in the rising period of the initialization period, a ramp voltage that gradually rises is applied to the scan electrode while the data electrode is held at the voltage Vd. Accordingly, after a weak discharge is generated between the scan electrode and the sustain electrode, a weak discharge is generated between the scan electrode and the data electrode. As a result, negative wall charges are accumulated on the scan electrodes, and positive wall charges are accumulated on the sustain electrodes. At this time, positive wall charges are accumulated in the data electrode.

  Further, during the fall period of the initialization period, a ramp voltage that gradually falls is applied to the scan electrode while the data electrode is held at the ground potential. As a result, a weak discharge is generated between the scan electrode and the data electrode and between the sustain electrode and the data electrode. As a result, the negative wall charges accumulated in the scan electrodes are reduced, and the positive wall charges accumulated in the sustain electrodes are reduced. At this time, positive wall charges are accumulated in the data electrode.

  In this way, at the start of the address period, negative wall charges are accumulated on the scan electrodes and positive wall charges are accumulated on the data electrodes. In this state, a negative address pulse is applied to the scan electrode and a positive address pulse is applied to the data electrode in the address period. In this case, the wall charge increases the voltage between the scan electrode and the data electrode, and the address discharge is stably generated between the scan electrode and the data electrode.

  At this time, since positive wall charges are accumulated in the sustain electrode, a large address discharge is generated between the scan electrode and the sustain electrode. Accordingly, when the distance between adjacent discharge cells is small, crosstalk occurs between adjacent discharge cells, and erroneous discharge is likely to occur. Therefore, in order to prevent the occurrence of such crosstalk, a panel driving method described below has been put into practical use.

(Conventional panel driving method 3)
FIG. 20 is an example of a panel drive waveform for preventing crosstalk occurring between adjacent discharge cells. Also in this example, the data electrode is kept at the voltage Vd higher than the ground potential during the rising period of the initialization period.

  In the drive waveform of FIG. 20, the phase difference TR for erasing discharge is smaller than the phase difference TR for erasing discharge in the driving waveform of FIG. The smaller the phase difference TR, the weaker the erase discharge. Therefore, in the drive waveform of FIG. 20, the erasing discharge is weaker than that of FIG. 19, and a large amount of positive wall charge remains in the scan electrode and a large amount of negative wall charge remains in the sustain electrode before the initialization period. . Thereby, the address discharge in the address period can be weakened. As a result, it is considered that crosstalk between adjacent discharge cells can be prevented.

  However, according to experiments by the present inventors, it has been found that the following phenomenon actually occurs. As shown in FIG. 20, in the rising period of the initialization period, a ramp voltage that gradually increases from the voltage Vm by the voltage Vset is applied to the scan electrode, the sustain electrode is kept at the ground potential, and the data electrode is kept at the ground potential. Is maintained at a high voltage Vd.

  As described above, many positive wall charges are accumulated in the scan electrodes and many negative wall charges are accumulated in the sustain electrodes before the initialization period. Therefore, when the voltage Vm is applied to the scan electrode, a strong discharge is generated between the sustain electrode and the data electrode, and accordingly, a strong discharge is generated between the scan electrode and the sustain electrode.

  Due to the occurrence of such strong discharge, the wall charges accumulated in the scan electrode, the sustain electrode and the data electrode are erased. As a result, even when a ramp voltage rising by the voltage Vset is applied to the scan electrode, the voltage between the scan electrode and the sustain electrode does not exceed the discharge start voltage, and a weak discharge is generated between the scan electrode and the sustain electrode. Can not be made.

  Therefore, it becomes difficult to adjust the wall charges of the scan electrode, the sustain electrode, and the data electrode to an amount necessary for the address discharge in the address period.

  Therefore, it is conceivable to increase the lamp voltage applied to the scan electrodes in order to generate a weak discharge after the above-described strong discharge. However, the cost of the drive circuit increases.

  An object of the present invention is to provide a plasma display apparatus and a driving method thereof capable of preventing a crosstalk generated between adjacent discharge cells and forming a desired amount of wall charges on a plurality of electrodes constituting the discharge cells. Is to provide.

  (1) A plasma display device according to one aspect of the present invention includes a plasma display panel having a plurality of discharge cells at intersections of scan electrodes, sustain electrodes, and a plurality of data electrodes, and one field period includes a plurality of subfields. A plasma display device driven by a subfield method, comprising: a scan electrode drive circuit for driving a scan electrode; a sustain electrode drive circuit for driving a sustain electrode; and a data electrode drive circuit for driving a data electrode; At least one of the subfields includes an initialization period in which wall charges of the plurality of discharge cells are adjusted to a state in which address discharge is possible, and the scan electrode driving circuit performs the initialization discharge in the initialization period. A ramp voltage changing from the first potential to the second potential is applied to the scan electrode, and the sustain electrode drive circuit A voltage that changes from the third potential to the fourth potential is applied to the sustain electrode so that the potential difference between the scan electrode and the sustain electrode becomes larger before the start of the change to the first potential. The electrode driving circuit operates in a fifth manner so that the potential difference between the scan electrode and each data electrode becomes small in synchronization with the change in the voltage of the sustain electrode before the start of the change of the scan electrode to the first potential. A voltage that changes from a potential to a sixth potential is applied to each data electrode.

  In this plasma display device, at least one subfield of the plurality of subfields includes an initialization period in which the wall charges of the plurality of discharge cells are adjusted to a state where address discharge is possible. In this initialization period, a ramp voltage that changes from the first potential to the second potential is applied to the scan electrodes by the scan electrode driving circuit.

  On the other hand, before the start of the change of the scan electrode to the first potential in the initialization period, the third potential is changed to the fourth potential so that the potential difference between the scan electrode and the sustain electrode becomes large. A voltage is applied to the sustain electrodes by the sustain electrode drive circuit. In addition, the potential difference between the scan electrode and each data electrode is small in synchronization with the change of the voltage applied to the sustain electrode before the start of the change of the scan electrode to the first potential during the initialization period. A voltage that changes from the fifth potential to the sixth potential is applied to the data electrode by the data electrode driving circuit.

  As described above, the potential difference between the sustain electrode and each data electrode increases before the start of the change of the scan electrode to the first potential, and a discharge occurs between the sustain electrode and each data electrode. . As a result, wall charges on the sustain electrode and each data electrode are erased or reduced.

  Further, when a weak erase discharge is performed at the end of the previous sustain period to prevent crosstalk, a large amount of wall charges are accumulated on the sustain electrode before the start of the initialization period. Even in such a case, since the wall charges are erased or reduced by the discharge between the sustain electrode and each data electrode, the change between the scan electrode and the sustain electrode at the start of the change to the first potential of the scan electrode. This prevents the occurrence of strong discharge. In this case, wall charges remain on the scan electrodes and the sustain electrodes.

  Thereafter, as described above, while the ramp voltage applied to the scan electrode changes from the first potential to the second potential, the voltage between the scan electrode and the sustain electrode is reliably set higher than the discharge start voltage. can do. Thereby, a weak initializing discharge is generated between the scan electrode and the sustain electrode. As a result, the wall charges of the plurality of discharge cells can be reliably adjusted to an amount necessary for address discharge.

  Further, since the voltage of each data electrode becomes the fifth potential so that the potential difference between the scan electrode and each data electrode becomes small, it is possible to prevent a strong discharge from occurring between the scan electrode and each data electrode. In addition, the occurrence of strong discharge between the scan electrode and the sustain electrode is prevented.

  As a result, the wall charges on the scan electrodes, the sustain electrodes, and the data electrodes are not erased by the strong discharge, and the wall charges of the plurality of discharge cells can be adjusted to values appropriate for the address discharge.

  (2) The data electrode driving circuit changes the voltage of each data electrode from the sixth potential to the fifth potential before the scan electrode starts to change to the first potential, and then The voltage of each data electrode may be returned to the sixth potential again after the start of the change to the first potential.

  In this case, ripples are prevented from occurring in the voltage of each data electrode when the ramp voltage changes. Thereby, an element with a low breakdown voltage can be used for the data electrode driving circuit.

  (3) The data electrode drive circuit may maintain the voltage of each data electrode at the sixth potential during the application of the ramp voltage. In this case, the voltage applied to each data electrode can be easily controlled.

  (4) The second potential is a positive potential higher than the first potential, the third potential is a positive potential higher than the fourth potential, and the sixth potential is the fifth potential It may be a positive potential higher than the potential.

  In this case, the ramp voltage applied to the scan electrode rises from the first potential to the second potential. In addition, the voltage applied to the sustain electrode falls from the third potential to the fourth potential before the start point of the change of the scan electrode to the first potential. Further, the voltage applied to each data electrode rises from the fifth potential to the sixth potential before the start of the change of the scan electrode to the first potential. Thus, since a positive voltage is applied to the scan electrode, the sustain electrode, and each data electrode, the configuration of the power supply circuit is not complicated.

  (5) The fourth potential and the sixth potential are set so that the first discharge is generated between the sustain electrode and each data electrode, and the ramp voltage is set to the first potential after the first discharge. The second discharge is set to occur between the scan electrode and the sustain electrode during the change from the first potential to the second potential, and the discharge current at the second discharge is higher than the discharge current at the first discharge. It may be small.

  In this case, since the discharge current at the time of the second discharge is smaller than the discharge current at the time of the first discharge, the wall charges accumulated on the scan electrodes and the wall charges accumulated on the sustain electrodes are erased. It is adjusted to an appropriate amount.

  (6) The scan electrode drive circuit applies a pulse voltage having a seventh potential to the scan electrode at the end of the sustain period preceding the initialization period, and the sustain electrode drive circuit discharges the discharge cell in which the sustain discharge has been performed. In order to reduce the wall charge, a voltage that changes from the fourth potential to the third potential may be applied to the sustain electrode during the period of the pulse voltage.

  In this case, at the end of the sustain period preceding the initialization period, it is possible to leave many wall charges on the scan electrode and the sustain electrode by a weak erasing discharge. Thereby, in the address period after the initialization period, the address discharge is weakened, and crosstalk generated between adjacent discharge cells can be prevented.

  (7) The scan electrode driving circuit scans the ramp pulse voltage having the seventh potential at the end of the sustain period before the initialization period in order to reduce the wall charge of the discharge cell that has performed the sustain discharge. When applied to the electrode, the leading edge of the ramp pulse voltage changes more slowly than the trailing edge, and the sustain electrode driving circuit may hold the sustain electrode at the third potential during the ramp pulse voltage.

  In this case, since the leading edge of the ramp pulse voltage gradually changes at the end of the sustain period preceding the initialization period, a large amount of wall charges may remain on the scan electrode and the sustain electrode due to the weak erase discharge. It becomes possible. Thereby, in the address period after the initialization period, the address discharge is weakened, and crosstalk generated between adjacent discharge cells can be prevented.

  (8) A driving method of a plasma display device according to another aspect of the present invention includes a plasma display panel having a plurality of discharge cells at intersections of scan electrodes, sustain electrodes, and a plurality of data electrodes. A driving method of a plasma display device driven by a subfield method including a subfield, the method comprising: driving a scan electrode, driving a sustain electrode, and driving a data electrode, and a plurality of subfields At least one of the subfields includes an initialization period in which wall charges of the plurality of discharge cells are adjusted to a state in which address discharge is possible, and the step of driving the scan electrode is performed for the initialization discharge in the initialization period. Applying a ramp voltage varying from the first potential to the second potential to the scan electrode, and maintaining The step of driving the pole changes from the third potential to the fourth potential so that the potential difference between the scan electrode and the sustain electrode is increased before the start of the change of the scan electrode to the first potential. A step of applying a voltage to the sustain electrode, and the step of driving the data electrode includes the scan electrode and each data in synchronization with a change in the voltage of the sustain electrode before the start of the change of the scan electrode to the first potential. A step of applying a voltage that changes from the fifth potential to the sixth potential to each data electrode so that the potential difference between the electrodes may be reduced may be included.

  In this method for driving a plasma display device, at least one subfield of the plurality of subfields includes an initialization period in which the wall charges of the plurality of discharge cells are adjusted to a state in which address discharge is possible. In this initialization period, a ramp voltage that changes from the first potential to the second potential is applied to the scan electrodes.

  On the other hand, before the start of the change of the scan electrode to the first potential in the initialization period, the third potential is changed to the fourth potential so that the potential difference between the scan electrode and the sustain electrode becomes large. A voltage is applied to the sustain electrode. In addition, the potential difference between the scan electrode and each data electrode is small in synchronization with the change of the voltage applied to the sustain electrode before the start of the change of the scan electrode to the first potential during the initialization period. A voltage that changes from the fifth potential to the sixth potential is applied to the data electrode.

  As described above, the potential difference between the sustain electrode and each data electrode increases before the start of the change of the scan electrode to the first potential, and a discharge occurs between the sustain electrode and each data electrode. . As a result, wall charges on the sustain electrode and each data electrode are erased or reduced.

  Further, when a weak erase discharge is performed at the end of the previous sustain period to prevent crosstalk, a large amount of wall charges are accumulated on the sustain electrode before the start of the initialization period. Even in such a case, since the wall charges are erased or reduced by the discharge between the sustain electrode and each data electrode, the change between the scan electrode and the sustain electrode at the start of the change to the first potential of the scan electrode. This prevents the occurrence of strong discharge. In this case, wall charges remain on the scan electrodes and the sustain electrodes.

  Thereafter, as described above, while the ramp voltage applied to the scan electrode changes from the first potential to the second potential, the voltage between the scan electrode and the sustain electrode is reliably set higher than the discharge start voltage. can do. Thereby, a weak initializing discharge is generated between the scan electrode and the sustain electrode. As a result, the wall charges of the plurality of discharge cells can be reliably adjusted to an amount necessary for address discharge.

  Further, since the voltage of each data electrode becomes the fifth potential so that the potential difference between the scan electrode and each data electrode becomes small, it is possible to prevent a strong discharge from occurring between the scan electrode and each data electrode. In addition, the occurrence of strong discharge between the scan electrode and the sustain electrode is prevented.

  As a result, the wall charges on the scan electrodes, the sustain electrodes, and the data electrodes are not erased by the strong discharge, and the wall charges of the plurality of discharge cells can be adjusted to values appropriate for the address discharge.

  According to the present invention, it is possible to prevent crosstalk generated between adjacent discharge cells and to form a desired amount of wall charges on a plurality of electrodes constituting the discharge cells.

FIG. 1 is an exploded perspective view showing a part of a plasma display panel in a plasma display apparatus according to an embodiment of the present invention. FIG. 2 is an electrode array diagram of a panel according to an embodiment of the present invention. FIG. 3 is a circuit block diagram of a plasma display device according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a driving waveform applied to each electrode of the plasma display device according to the embodiment of the present invention. 5 is a partially enlarged view of the drive waveform of FIG. FIG. 6 is an enlarged view showing another example of a driving waveform applied to each electrode of the plasma display device according to one embodiment of the present invention. FIG. 7 is a view showing still another example of the driving waveform applied to each electrode of the plasma display device according to the embodiment of the present invention. FIG. 8 is a partially enlarged view of the drive waveform of FIG. FIG. 9 is a circuit diagram showing the configuration of the scan electrode driving circuit of FIG. FIG. 10 is a timing chart of control signals supplied to the scan electrode drive circuit of FIG. 9 during the initialization period of the first SF of FIG. 11 is a circuit diagram showing the configuration of the sustain electrode driving circuit of FIG. FIG. 12 is a timing chart of the control signal applied to the sustain electrode driving circuit before and after the initializing period of the first SF of FIG. FIG. 13 is a circuit diagram showing the configuration of the data electrode driving circuit of FIG. FIG. 14 is a timing chart of control signals supplied to the data electrode driving circuit during the initialization period of the first SF of FIG. 15 is a circuit diagram showing another configuration of the scan electrode driving circuit of FIG. FIG. 16 is a timing chart of control signals supplied to the scan electrode driving circuit of FIG. 15 during the initialization period of the first SF of FIG. FIG. 17 is a circuit diagram showing still another configuration of the scan electrode driving circuit of FIG. FIG. 18 is a timing chart of control signals supplied to the scan electrode driving circuit of FIG. 17 during the initialization period of the first SF of FIG. FIG. 19 shows an example of a panel drive voltage waveform using the panel drive method of Patent Document 2. FIG. 20 shows an example of a panel drive waveform for preventing crosstalk between adjacent discharge cells.

  Hereinafter, a plasma display device and a driving method thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Panel FIG. 1 is an exploded perspective view showing a part of a plasma display panel in a plasma display apparatus according to an embodiment of the present invention.

  A plasma display panel (hereinafter abbreviated as “panel”) 10 includes a glass front substrate 21 and a rear substrate 31 that are arranged to face each other. A discharge space is formed between the front substrate 21 and the rear substrate 31. A plurality of pairs of scan electrodes 22 and sustain electrodes 23 are formed in parallel with each other on the front substrate 21. Each pair of scan electrode 22 and sustain electrode 23 constitutes a display electrode. A dielectric layer 24 is formed so as to cover the scan electrode 22 and the sustain electrode 23, and a protective layer 25 is formed on the dielectric layer 24.

  A plurality of data electrodes 32 covered with an insulator layer 33 are provided on the back substrate 31, and a grid-like partition wall 34 is provided on the insulator layer 33. A phosphor layer 35 is provided on the surface of the insulator layer 33 and the side surfaces of the partition walls 34. The front substrate 21 and the rear substrate 31 are arranged to face each other so that the plurality of pairs of scan electrodes 22 and sustain electrodes 23 and the plurality of data electrodes 32 intersect vertically, and between the front substrate 21 and the rear substrate 31. A discharge space is formed. In the discharge space, for example, a mixed gas of neon and xenon is enclosed as a discharge gas. Note that the structure of the panel is not limited to that described above, and for example, a structure including a stripe-shaped partition may be used.

  FIG. 2 is an electrode array diagram of the panel according to the embodiment of the present invention. N scan electrodes SC1 to SCn (scan electrode 22 in FIG. 1) and n sustain electrodes SU1 to SUn (sustain electrode 23 in FIG. 1) are arranged along the row direction, and m scan electrodes are arranged along the column direction. Data electrodes D1 to Dm (data electrode 32 in FIG. 1) are arranged. n and m are each a natural number of 2 or more. A discharge cell DC is formed at a portion where one pair of scan electrode SCi (i = 1 to n) and sustain electrode SUi (i = 1 to n) intersects with one data electrode Dj (j = 1 to m). Has been. Thereby, m × n discharge cells are formed in the discharge space.

(2) Configuration of Plasma Display Device FIG. 3 is a circuit block diagram of a plasma display device according to an embodiment of the present invention.

  The plasma display device includes a panel 10, an image signal processing circuit 51, a data electrode drive circuit 52, a scan electrode drive circuit 53, a sustain electrode drive circuit 54, a timing generation circuit 55, and a power supply circuit (not shown).

  The image signal processing circuit 51 converts the image signal sig into image data corresponding to the number of pixels of the panel 10, divides the image data of each pixel into a plurality of bits corresponding to a plurality of subfields, and drives these data electrodes Output to the circuit 52.

  The data electrode drive circuit 52 converts the image data for each subfield into signals corresponding to the data electrodes D1 to Dm, and drives the data electrodes D1 to Dm based on the signals.

  The timing generation circuit 55 generates a timing signal based on the horizontal synchronization signal H and the vertical synchronization signal V, and outputs these timing signals to respective drive circuit blocks (image signal processing circuit 51, data electrode drive circuit 52, scan electrode drive). Circuit 53 and sustain electrode drive circuit 54).

  Scan electrode drive circuit 53 supplies a drive waveform to scan electrodes SC1 to SCn based on the timing signal, and sustain electrode drive circuit 54 supplies a drive waveform to sustain electrodes SU1 to SUn based on the timing signal.

(3) Panel Driving Method A panel driving method in this embodiment will be described. FIG. 4 is a diagram illustrating an example of a driving waveform applied to each electrode of the plasma display device according to the embodiment of the present invention. FIG. 5 is a partially enlarged view of the drive waveform of FIG.

  4 and 5, the drive waveform applied to one scan electrode among scan electrodes SC1 to SCn, one drive waveform among sustain electrodes SU1 to SUn, and one of data electrodes D1 to Dn. A drive waveform is shown.

  In the present embodiment, each field is divided into a plurality of subfields. In the present embodiment, one field is divided into 10 subfields (hereinafter abbreviated as first SF, second SF,..., And 10th SF) on the time axis. A pseudo subfield (hereinafter abbreviated as pseudo SF) is provided in a period from the 10th SF of each field to the next field.

  FIG. 4 shows from the sustaining period of the 10th SF of the previous field to the initialization period of the 3rd SF of the next field. FIG. 5 shows the sustain period from the tenth SF of FIG. 4 to the first SF write period of the next field.

  In the following description, a voltage generated by wall charges accumulated on a dielectric layer or a phosphor layer covering the electrode is referred to as a wall voltage on the electrode.

  As shown in FIGS. 4 and 5, the voltage of the sustain electrode SUi is raised to Ve1 after a predetermined time (phase difference TR) from the rise of the voltage of the scan electrode SCi to Vs at the end of the tenth SF of the previous field. Thereby, an erasing discharge is generated between scan electrode SCi and sustain electrode SUi, and the positive wall charge accumulated in scan electrode SCi and the negative wall charge accumulated in sustain electrode SUi are reduced. In the present embodiment, the phase difference TR is set small so that the erasing discharge is weakened. Generally, the phase difference TR for erasing discharge as described above is about 450 nsec. In contrast, in this example, the phase difference TR is set to 150 nsec, for example.

  Thus, by setting the phase difference TR to be small, the erasing discharge between the scan electrode SCi and the sustain electrode SUi becomes weak. As a result, a large amount of positive wall charges remains on the scan electrode SCi, and a large amount of negative wall charges remains on the sustain electrode SUi. At this time, positive wall charges are accumulated on the data electrode Dj.

  In the first half of the pseudo SF, the sustain electrode SUi is held at the voltage Ve1, the data electrode Dj is held at the ground potential (reference voltage), and the ramp voltage is applied to the scan electrode SCi. The ramp voltage gradually decreases from the positive voltage Vi5 slightly higher than the ground potential toward the negative voltage Vi4 that is equal to or lower than the discharge start voltage.

  Thereby, a weak discharge is generated between scan electrode SCi and data electrode Dj and between scan electrode SCi and sustain electrode SUi. As a result, the positive wall charge on the scan electrode SCi is slightly increased, and the negative wall charge on the sustain electrode SUi is slightly increased. Further, positive wall charges are accumulated on the data electrode Dj. In this way, the wall charges of all the discharge cells DC are adjusted almost uniformly.

  In the second half of the pseudo SF, the scan electrode SCi is held at the ground potential.

  In this way, at the end of the pseudo SF, a large amount of positive wall charge is accumulated in the scan electrode SCi, and a large amount of negative wall charge is accumulated in the sustain electrode SUi.

  After that, as shown in FIG. 5, at the time t1 immediately before the first SF of the next field, the voltage of the sustain electrode SUi is lowered from Ve1 to the ground potential. Then, at the start time t2 of the initialization period of the first SF, a pulsed positive voltage Vd is applied to the data electrode Dj.

  Immediately before time t2, a large amount of negative wall charges is accumulated on the sustain electrode SUi, and positive wall charges are accumulated on the data electrode Dj. When the voltage of data electrode Dj rises to Vd, the voltage between sustain electrode SUi and data electrode Dj becomes a value obtained by adding the wall voltage on data electrode Dj and the wall voltage on sustain electrode SUi to voltage Vd. . As a result, when the voltage between sustain electrode SUi and data electrode Dj exceeds the discharge start voltage, strong discharge is generated between sustain electrode SUi and data electrode Dj.

  Due to this strong discharge, the negative wall charges on the sustain electrodes SUi are erased, and zero or a small amount of positive wall charges are accumulated on the sustain electrodes SUi. Further, the wall charges on the data electrode Dj are erased, and zero or a small amount of negative wall charges are accumulated on the data electrode Dj. At this time, the positive wall charges on the scan electrode SCi are also slightly erased.

  Thereafter, the voltage of the scan electrode SCi is raised at time t3, and then the scan electrode SCi is held at the positive voltage Vi1 at time t4. At this time t4, the voltage of the data electrode Dj is raised to Vd. At this time, since zero or a small amount of positive wall voltage is accumulated on sustain electrode SUi, strong discharge does not occur between scan electrode SCi and sustain electrode SUi.

  A ramp voltage is applied to scan electrode SCi at time t4. The ramp voltage gradually increases from the positive voltage Vi1 that is equal to or lower than the discharge start voltage to the positive voltage Vi2 that exceeds the discharge start voltage from time t5 to time t6. At this time, since the data electrode Dj is held at the voltage Vd, it is possible to prevent a strong discharge from occurring between the scan electrode SCi and the data electrode Dj. Further, sustain electrode SUi is held at the ground potential.

  When the voltage between scan electrode SCi and sustain electrode SUi exceeds the discharge start voltage as the lamp voltage increases, a weak initializing discharge occurs between scan electrode SCi and sustain electrode SUi in all discharge cells DC. .

  Thereby, the positive wall charges accumulated on the scan electrode SCi are gradually erased, and the negative wall charges are accumulated on the scan electrode SCi. On the other hand, positive wall charges are accumulated on the sustain electrode SUi.

  At time t7, the voltage of scan electrode SCi falls, and at time t8, scan electrode SCi is held at voltage Vi3. At this time, a positive voltage Ve1 is applied to the sustain electrode SUi.

  At time t9, a negative ramp voltage is applied to scan electrode SCi. This ramp voltage drops from the positive voltage Vi3 to the negative voltage Vi4 from time t9 to time t10. At time t9, the voltage of the data electrode Dj is lowered and held at the ground potential.

  From time t9 to time t10, the voltage of the sustain electrode SUi is held at the positive voltage Ve1. Thus, when the voltage between scan electrode SCi and sustain electrode SUi exceeds the discharge start voltage as the lamp voltage decreases, weak initializing discharge occurs in all discharge cells DC.

  Thereby, the negative wall charges accumulated on scan electrode SCi are gradually erased from time t9 to time t10, and a small amount of negative wall charge remains on scan electrode SCi at time t10. On the other hand, from time point t9 to time point t10, the positive wall charges accumulated on sustain electrode SUi are gradually erased, and at time point t10, negative wall charges are accumulated on sustain electrode SUi. Further, positive wall charges are accumulated in the data electrode Dj from time t9 to time t10.

  At time t10, the voltage of scan electrode SCi is raised to the ground potential. Thereby, the initialization period ends, and the wall voltage on scan electrode SCi, the wall voltage on sustain electrode SUi, and the wall voltage on data electrode Dj are adjusted to values suitable for the write operation. Specifically, a small amount of negative wall charge is accumulated on scan electrode SCi, negative wall charge is accumulated on sustain electrode SUi, and positive wall charge is accumulated on data electrode Dj.

  As described above, in the initializing period of the first SF, the all-cell initializing operation for generating the initializing discharge in all the discharge cells DC is performed.

  Returning to FIG. 4, in the address period of the first SF, the voltage Ve2 is applied to the sustain electrode SUi, and the voltage of the scan electrode SCi is held at the ground potential. Next, a scan pulse having a negative voltage Va is applied to scan electrode SC1 in the first row, and data electrode Dk (k is any one of 1 to m) of the discharge cell that should emit light in the first row of data electrodes Dj. A write pulse having a positive voltage Vd.

  Then, the voltage at the intersection of the data electrode Dk and the scan electrode SC1 becomes a value obtained by adding the wall voltage on the data electrode Dk and the wall voltage on the scan electrode SC1 to the externally applied voltage (Vd−Va). Over voltage. Thereby, address discharge is generated between data electrode Dk and scan electrode SC1, and between sustain electrode SU1 and scan electrode SC1.

  Here, in the present embodiment, as described above, negative wall charges are accumulated in scan electrode SCi and sustain electrode SUi, and positive wall charges are accumulated in data electrode Dj at the start of the address period. . Therefore, the address discharge between sustain electrode SU1 and scan electrode SC1 is weakened.

  Thereby, even when the distance between adjacent discharge cells is set small in the panel of FIG. 1, it is possible to prevent crosstalk from occurring between adjacent discharge cells DC.

  Due to the address discharge, positive wall charges are accumulated on scan electrode SC1 of discharge cell DC, negative wall charges are accumulated on sustain electrode SU1, and negative wall charges are also accumulated on data electrode Dk. The

  In this manner, the address operation is performed in which the address discharge is generated in the discharge cells DC to emit light in the first row and the wall charges are accumulated on the respective electrodes. On the other hand, the voltage in the discharge cell DC at the intersection of the data electrode Dh (h ≠ k) to which the address pulse is not applied and the scan electrode SC1 does not exceed the discharge start voltage, so that address discharge does not occur.

  The address operation described above is sequentially performed from the discharge cell DC in the first row to the discharge cell in the nth row, and the address period ends.

  In the subsequent sustain period, sustain electrode SUi is returned to the ground potential, and sustain pulse voltage Vs having voltage Vs is applied to scan electrode SCi. At this time, in the discharge cell DC in which the address discharge is generated in the address period, the voltage between the scan electrode SCi and the sustain electrode SUi is the sustain pulse voltage Vs, the wall voltage on the scan electrode SCi, and the sustain electrode SUi. The wall voltage is added and exceeds the discharge start voltage.

  As a result, a sustain discharge occurs between scan electrode SCi and sustain electrode SUi, and discharge cell DC emits light. As a result, negative wall charges are accumulated on scan electrode SCi, positive wall charges are accumulated on sustain electrode SUi, and positive wall charges are accumulated on data electrode Dk. In the discharge cells DC in which no address discharge has occurred in the address period, no sustain discharge occurs, and the wall charge state at the end of the initialization period is maintained.

  Subsequently, scan electrode SCi is returned to the ground potential, and a sustain pulse having voltage Vs is applied to sustain electrode SUi. Then, in the discharge cell DC in which the sustain discharge has occurred, since the voltage between the sustain electrode SUi and the scan electrode SCi exceeds the discharge start voltage, the sustain discharge occurs again between the sustain electrode SUi and the scan electrode SCi, and the sustain cell is maintained. Negative wall charges are accumulated on the electrode SUi, and positive wall charges are accumulated on the scan electrode SCi.

  Thereafter, similarly, by applying a predetermined number of sustain pulses alternately to scan electrode SCi and sustain electrode SUi, sustain discharge is continuously performed in discharge cell DC in which the address discharge has occurred in the address period.

  Before the end of the sustain period, the voltage applied to the sustain electrode SUi is raised to Ve1 after a predetermined time (phase difference TR) after the voltage applied to the scan electrode SCi rises to Vs. As a result, similarly to the end of the tenth SF described with reference to FIG. 5, a weak erasing discharge occurs between the scan electrode SCi and the sustain electrode SUi.

  In the initialization period of the second SF, similarly to the pseudo SF described with reference to FIG. 5, the voltage of the sustain electrode SUi is held at Ve1, the data electrode Dj is held at the ground potential, and the positive voltage is applied to the scan electrode SCi. A ramp voltage that gently falls from Vi5 toward negative voltage Vi4 is applied. Then, a weak initializing discharge is generated in the discharge cell DC in which the sustain discharge has occurred in the sustain period of the previous subfield.

  Thereby, the wall voltage on scan electrode SCi and the wall voltage on sustain electrode SUi are weakened, and the wall voltage on data electrode Dk is also adjusted to a value suitable for the write operation.

  On the other hand, in the discharge cell DC in which the address discharge and the sustain discharge did not occur in the previous subfield, no discharge occurred, and the wall charge state at the end of the initialization period of the previous subfield was maintained. It is.

  As described above, in the initializing period of the second SF, the selective initializing operation for selectively generating the initializing discharge in the discharge cell DC in which the sustain discharge has occurred in the immediately preceding subfield is performed.

  In the second SF address period, as in the first SF address period, the address operation is sequentially performed from the discharge cell in the first row to the discharge cell in the nth row, and the address period ends. Since the operation in the subsequent sustain period is the same as the operation in the sustain period of the first SF except for the number of sustain pulses, description thereof is omitted.

  In the subsequent initialization period from the third SF to the tenth SF, the selective initialization operation is performed as in the initialization period of the second SF. In the address period from the third SF to the tenth SF, the address operation is performed by applying the voltage Ve2 to the sustain electrode SUi as in the second SF. In the sustain period from the third SF to the tenth SF, the same sustain operation as that of the first SF is performed except for the number of sustain pulses.

(4) Other examples of drive waveforms (4-a) Regarding wall charge adjustment Wall charges of scan electrode SCi and sustain electrode SUi before the start of pseudo SF are adjusted by applying the following drive waveforms to each electrode. You may go. FIG. 6 is an enlarged view showing another example of a driving waveform applied to each electrode of the plasma display device according to one embodiment of the present invention.

  As shown in FIG. 6, in this example, in order to perform weak erase discharge before selective initialization, the sustain electrode SUi and the data electrode Dj are held at the ground potential at the end of the tenth SF of the previous field. A ramp voltage is applied to the scan electrode SCi. This ramp voltage rises gradually from the ground potential toward the positive voltage Vs.

  Here, in the discharge cell DC in which the sustain discharge has occurred, positive wall charges are accumulated in the scan electrode SCi, and negative wall charges are accumulated in the sustain electrode SUi. Therefore, as described above, when the ramp voltage is applied to scan electrode SCi, in discharge cell DC in which the sustain discharge has occurred, the voltage between scan electrode SCi and sustain electrode SUi exceeds the discharge start voltage. Again, a weak erase discharge is generated between sustain electrode SUi and scan electrode SCi.

  As a result, the positive wall charges accumulated in scan electrode SCi and the negative wall charges accumulated in sustain electrode SUi are slightly reduced, so that a lot of positive wall charges remain in scan electrode SCi, and the negative wall charges in sustain electrode SUi. A lot of charge remains. At this time, positive wall charges are accumulated on the data electrode Dj.

  Thus, similarly to the example of FIGS. 4 and 5, the selective initialization operation is performed in the subsequent pseudo-SF, and the all-cell initialization operation is performed in the initialization period of the first SF in the next field, whereby the scan electrode SCi. The upper wall voltage, the wall voltage on the sustain electrode SUi, and the wall voltage on the data electrode Dj are adjusted to values suitable for the write operation.

(4-b) Regarding Setting of Initialization Period in Field In the example of FIG. 4, the initialization period is provided at the beginning of the first SF that is the first subfield of the field. Hereinafter, an example in which the initialization period is provided between predetermined subfields in the field will be described.

  FIG. 7 is a view showing still another example of the drive waveform applied to each electrode of the plasma display apparatus according to the embodiment of the present invention, and FIG. 8 is a partially enlarged view of the drive waveform of FIG. .

  The drive waveforms shown in FIGS. 7 and 8 will be described while referring to differences from the drive waveforms shown in FIGS. As shown in FIG. 7, in the driving waveform of this example, after the pseudo SF of the previous field, all cells are not initialized by the first SF of the next field.

  That is, the first SF does not have an initialization period, and the other subfields have an initialization period. In addition, after the erase operation is performed in the first SF, the all-cell initialization operation is performed in the initialization period of the second SF.

  FIG. 7 shows from the sustaining period of the 10th SF of the previous field to the initialization period of the 3rd SF of the next field.

  In the address period of the first SF, similarly to the address period described with reference to FIG. 4, the scan pulse having the negative voltage Va is applied to the sustain electrode SUi, and the address pulse having the positive voltage Vd is applied to the data electrode Dk. Apply.

  Thereby, address discharge is generated between data electrode Dk and scan electrode SC1, and between sustain electrode SU1 and scan electrode SC1. This address operation is sequentially performed from the discharge cell DC in the first row to the discharge cell in the nth row, and the address period ends.

  In the subsequent sustain period, similarly to the sustain period described with reference to FIG. 4, sustain electrode SUi is returned to the ground potential, and a sustain pulse having voltage Vs is applied to scan electrode SCi.

  Thereby, in the discharge cell DC in which the address discharge is generated in the address period, a sustain discharge occurs between the scan electrode SCi and the sustain electrode SUi, and the discharge cell DC emits light. Thereafter, similarly, by applying a predetermined number of sustain pulses alternately to scan electrode SCi and sustain electrode SUi, sustain discharge is continuously performed in discharge cell DC in which the address discharge has occurred in the address period.

  Here, as shown in FIG. 8, in the first SF, after the end of the sustain period, an erasing period is provided before the start of the second SF.

  In the erase period, similarly to the end of the sustain period of the 10th SF of the previous field described with reference to FIGS. 4 and 5, a predetermined time (set to a small value after the voltage of the scan electrode SCi is raised to Vs) ( After the phase difference TR), the voltage of the sustain electrode SUi is raised to Ve1.

  As a result, a weak erase discharge is generated between scan electrode SCi and sustain electrode SUi. Accordingly, a large amount of positive wall charges can be left in scan electrode SCi, and a large amount of negative wall charges can be left in sustain electrode SUi. In this state, the first SF ends.

  After that, as shown in FIG. 8, in the initialization period set at the beginning of the second SF, the all-cell initialization operation similar to the example of FIGS. 4 and 5 is performed. Thereafter, in the address period and the sustain period in the second SF, the address operation and the sustain operation similar to those in the examples of FIGS. 4 and 5 are performed.

  The third SF to the tenth SF following the second SF have an initialization period, an address period, and a sustain period, respectively, and a selective initialization operation is performed in these initialization periods.

  As described above, in the plasma display device according to the present embodiment, an initialization period for performing the all-cell initialization operation may be provided between predetermined subfields in the field.

(5) Circuit Configuration and Operation Control of Scan Electrode Drive Circuit 53 (5-a) Circuit Configuration FIG. 9 is a circuit diagram showing the configuration of scan electrode drive circuit 53 in FIG. In the following description, an example of a positive pulse that discharges when the drive voltage rises is shown, but a negative pulse that discharges when the drive voltage falls may be used.

  9 includes FETs (field effect transistors, hereinafter abbreviated as transistors) Q11 to Q22, recovery capacitors C11, capacitors C12 to C15, recovery coils L11 and L12, power supply terminals V11 to V14, and diodes. DD11 to DD14 are included.

  The transistor Q13 of the scan electrode driving circuit 53 is connected between the power supply terminal V11 and the node N13, and the control signal S13 is input to the gate. A voltage Vi1 is applied to the power supply terminal V11. The transistor Q14 is connected between the node N13 and the ground terminal, and a control signal S14 is input to a gate.

  The recovery capacitor C11 is connected between the node N11 and the ground terminal. Transistor Q11 and diode DD11 are connected in series between nodes N11 and N12a. Diode DD12 and transistor Q12 are connected in series between nodes N12b and N11. A control signal S11 is input to the gate of the transistor Q11, and a control signal S12 is input to the gate of the transistor Q12. The recovery coil L11 is connected between the node N12a and the node N13. The recovery coil L12 is connected between the node N12b and the node N13.

  Capacitor C12 is connected between nodes N14 and N13. Diode DD13 is connected between power supply terminal V12 and node N14. A voltage Vr is applied to the power supply terminal V12.

  The transistor Q15 is connected between the node N14 and the node N15, and a control signal S15 is input to a gate. Capacitor C13 is connected between node N14 and the gate of transistor Q15. The transistor Q16 is connected between the node N15 and the node N13, and a control signal S16 is input to a gate.

  The transistor Q17 is connected between the node N15 and the node N16, and a control signal S17 is input to a gate. The transistor Q18 is connected between the node N16 and the power supply terminal V13, and a control signal S18 is input to a gate. A voltage Vi4 is applied to the power supply terminal V13. Capacitor C14 is connected between node N16 and the gate of transistor Q18.

  Capacitor C15 is connected between nodes N16 and N17. Diode DD14 is connected between power supply terminal V14 and node N17. A voltage Vs is applied to the power supply terminal V14.

  The transistor Q19 is connected between the node N17 and the node N18, and a control signal S19 is input to a gate. The transistor Q20 is connected between the node N18 and the node N16, and a control signal S20 is input to a gate.

  The transistor Q21 is connected between the node N18 and the scan electrode SCi, and a control signal S21 is input to the gate. The transistor Q22 is connected between the node N16 and the scan electrode 12, and a control signal S22 is input to a gate.

  The control signals S11 to S22 are given as timing signals from the timing generation circuit 55 of FIG. 2 to the scan electrode driving circuit 53.

(5-b) Operation Control FIG. 10 is a timing chart of the control signals S11 to S22 supplied to the scan electrode drive circuit 53 of FIG. 9 during the initialization period of the first SF of FIG.

  At the start time t2 of the first SF, the control signals S11, S12, S13, S15, S18, S19, and S21 are each at a low level. Thereby, the transistors Q11, Q12, Q13, Q15, Q18, Q19, Q21 are turned off.

  Further, the control signals S14, S16, S17, S20, and S22 are each at a high level. Thereby, the transistors Q14, Q16, Q17, Q20, and Q22 are turned on. In this case, the voltage of the scan electrode SCi is the ground potential.

  At time t3, the control signal S11 becomes high level and the control signal S14 becomes low level. Thereby, the transistor Q11 is turned on and the transistor Q14 is turned off. Thereby, a current flows from the recovery capacitor C11 to the scan electrode SCi, and the voltage of the scan electrode SCi increases.

  Further, the control signal S11 becomes a low level immediately after the time point t3. Thereby, the transistor Q11 is turned off. At the same time, the control signal S13 is at a high level. Thereby, the transistor Q13 is turned on.

  In this case, the current flowing from the recovery capacitor C11 to the scan electrode SCi is interrupted, and the current flows from the power supply terminal V11 to the scan electrode SCi. As a result, the voltage of the scan electrode SCi rises and becomes Vi1 at time t4.

  Next, at time t5, the control signal S15 becomes high level and the control signal S16 becomes low level. Thereby, the transistor Q15 is turned on and the transistor Q16 is turned off.

  In this case, the current flowing from power supply terminal V11 to scan electrode SCi is interrupted, and the current flows from power supply terminal V12 to scan electrode SCi. At this time, since the voltage of the node N15 is held at Vi1, the voltage of the scan electrode SCi rises gently and becomes Vi2, that is, (Vi1 + Vr) at time t6.

  Next, at time t7, the control signal S15 becomes low level, and the control signal S16 becomes high level. Thereby, the transistor Q15 is turned off and the transistor Q16 is turned on. As a result, the voltage of the scan electrode SCi drops and becomes the voltage Vi1 (the above-mentioned voltage Vi3) of the power supply terminal V11 at time t8.

  Next, at time t9, the control signal S13 becomes low level, the control signal S17 becomes low level, and the control signal S18 becomes high level. Thereby, the transistor Q13 is turned off, the transistor Q17 is turned off, and the transistor Q18 is turned on. In this case, the voltage of the scan electrode SCi gradually decreases and becomes the voltage Vi4 of the power supply terminal V13 at time t10.

  At time t10, the control signal S19 becomes high level and the transistor Q19 is turned on. Thereby, the voltage Vs of the power supply terminal V14 is applied to the scan electrode SCi, so that the voltage of the scan electrode SCi becomes almost the ground potential.

  In the above configuration, a ramp waveform (not shown) that changes in a curve may be applied to the scan electrode SCi by adjusting the capacitance of the capacitor C13, for example.

(6) Circuit Configuration and Operation Control of Sustain Electrode Drive Circuit 54 (6-a) Circuit Configuration FIG. 11 is a circuit diagram showing the configuration of sustain electrode drive circuit 54 of FIG.

  Sustain electrode driving circuit 54 in FIG. 11 includes a sustain driver 540 and a voltage raising circuit 541.

  The sustain driver 540 of FIG. 11 includes n-channel FETs (field effect transistors, hereinafter abbreviated as transistors) Q101 to Q104, a recovery capacitor C101, a recovery coil L101, and diodes DD21 to DD24.

  The voltage raising circuit 541 includes n-channel FETs (field effect transistors, hereinafter abbreviated as transistors) Q105a, Q107, Q108, p-channel FETs (field effect transistors, abbreviated as transistors hereinafter) Q105b, a diode DD25, and a capacitor C102. Including.

  The transistor Q101 of the sustain driver 540 is connected between the power supply terminal V101 and the node N101, and the control signal S101 is input to the gate. A voltage Vs is applied to the power supply terminal V1.

  The transistor Q102 is connected between the node N101 and the ground terminal, and a control signal S102 is input to a gate. Node N101 is connected to sustain electrode SUi in FIG.

  The recovery capacitor C101 is connected between the node N103 and the ground terminal. Transistor Q103 and diode DD21 are connected in series between nodes N103 and N102. Diode DD22 and transistor Q104 are connected in series between nodes N102 and N103.

  The control signal S103 is input to the gate of the transistor Q103, and the control signal S104 is input to the gate of the transistor Q104. The recovery coil L101 is connected between the node N101 and the node N102. Diode DD23 is connected between node N102 and power supply terminal V101, and diode DD24 is connected between the ground terminal and node N102.

  The diode DD25 of the voltage raising circuit 541 is connected between the power supply terminal V111 and the node N104, and the voltage Ve1 is applied to the power supply terminal V111.

  Transistor Q105a and transistor Q105b are connected in series between nodes N104 and N101. Control signals S105a and S105b are input to the gates of transistors Q105a and Q105b, respectively. Capacitor C102 is connected between nodes N104 and N105.

  The transistor Q107 is connected between the node N105 and the ground terminal, and a control signal S107 is input to a gate. The transistor Q108 is connected between the power supply terminal V103 and the node N105, and a control signal S108 is input to a gate. A voltage VE2 is applied to the power supply terminal V103. The voltage VE2 satisfies the relationship VE2 = Ve2-Ve1, and is, for example, VE2 = 5 [V].

  The control signals S101 to S104, S105a, S105b, S107, and S108 are given as timing signals from the timing generation circuit 55 of FIG. 3 to the sustain electrode drive circuit 54.

(6-b) Operation Control FIG. 12 is a timing chart of the control signals S101 to S104, S105a, S105b, S107, and S108 supplied to the sustain electrode drive circuit 54 before and after the initializing period of the first SF of FIG. . The control signal S105b has a waveform that is inverted with respect to the waveform of the control signal S105a.

  First, at the time point t0 of the pseudo SF of the previous field, the control signals S101, S102, S103, S104, S105b, and S108 are each at a low level. Thereby, the transistors Q101, Q102, Q103, Q104, and Q108 are turned off, and the transistor Q105b is turned on. Also, the control signals S105a and S107 are each at a high level. Thereby, the transistors Q105a and Q107 are each turned on.

  In this case, a current flows from the power supply terminal V111 to the sustain electrode SUi through the node N104. Thereby, the voltage of the sustain electrode SUi is held at Ve1.

  Next, at the time t1 immediately before the end of the pseudo SF, that is, the time t1 immediately before the first SF of the next field, the control signal S104 becomes high level, the control signal S105a becomes low level, and the control signal S105b becomes high level. It has become.

  Thereby, the transistor Q104 is turned on and the transistors Q105a and Q105b are turned off. Thereby, a current flows from the sustain electrode SUi (node N101) to the recovery capacitor C101 through the recovery coil L101, the diode DD22, and the transistor Q104. At this time, the charge of the panel capacitance is recovered by the recovery capacitor C101. As a result, the voltage of sustain electrode SUi (node N101) drops.

  Further, immediately after the time point t1, the control signal S104 becomes a low level, and the control signal S102 becomes a high level. Thereby, the transistor Q104 is turned off and the transistor Q102 is turned on. Thereby, node N101 is grounded, and sustain electrode SUi is at the ground potential.

  The control signal S102 is at a high level from the start time t2 of the first SF of the next field to the time t8 when the voltage of the scan electrode SCi starts to decrease from Vi3 to the voltage Vi4. Thereby, sustain electrode SUi (node N101) is held at the ground potential.

  Here, at time t8, the control signal S102 becomes low level, the control signal S105a becomes high level, and the control signal S105b becomes low level. Thereby, the transistor Q102 is turned off, and the transistors Q105a and Q105b are turned on. Thereby, a current again flows from the power supply terminal V111 to the sustain electrode SUi through the node N104. Thereby, the voltage of the sustain electrode SUi is held at Ve1.

  Thereafter, after the initialization period has elapsed, at time t11 immediately after the start of the writing period, the control signal S107 becomes low level and the control signal S108 becomes high level. Thereby, the transistor Q107 is turned off and the transistor Q108 is turned on. Thereby, a current flows from power supply terminal V103 to node N105 through transistor Q108. As a result, the voltage at the node N105 rises to VE2. In this case, the voltage VE2 is added to the voltage Ve1 of the sustain electrode SUi. As a result, the voltage of sustain electrode SUi (node N101) rises to Ve2.

(7) Circuit Configuration and Operation Control of Data Electrode Drive Circuit 52 (7-a) Circuit Configuration FIG. 13 is a circuit diagram showing the configuration of data electrode drive circuit 52 in FIG.

  13 includes a plurality of p-channel FETs (field effect transistors, hereinafter abbreviated as transistors) Q211 to Q21m, and a plurality of n-channel FETs (field effect transistors, abbreviated as transistors hereinafter) Q221. Includes Q22m.

  A power supply terminal V201 is connected to the node N201. A voltage Vd is applied to the power supply terminal V201.

  Transistors Q211 to Q21m are connected between node N201 and nodes ND1 to NDm. Transistors Q221 to Q22m are connected between nodes ND1 to NDm and the ground terminal. The nodes ND1 to NDm are connected to the data electrode Dj in FIG.

  Control signals S201 to S20m are input to the gates of the plurality of transistors Q211 to Q21m, respectively. Control signals S201 to S20m are also input to the gates of the transistors Q221 to Q22m, respectively.

  The control signals S201 to S20m are given as timing signals from the timing generation circuit 55 in FIG. 2 to the data electrode driving circuit 52.

(7-b) Operation Control FIG. 14 is a timing chart of the control signals S201 to S20m supplied to the data electrode drive circuit 52 during the initialization period of the first SF of FIG.

  As shown in FIG. 14, at time t1 immediately before the first SF, the control signals S201 to S20m are both at the high level. Thereby, the transistors Q211 to Q21m are turned off and the transistors Q221 to 22m are turned on.

  In this case, nodes ND1 to NDm are connected to the ground terminal via transistors Q221 to 22m. Thereby, the data electrode Dj becomes the ground potential.

  Next, at the start time t2 of the first SF, both of the control signals S201 to S20m become low level. Thereby, the transistors Q211 to Q21m are turned on and the transistors Q221 to 22m are turned off.

  In this case, nodes ND1 to NDm are connected to node N201 via transistors Q211 to 21m. Thereby, a current flows from power supply terminal V201 to data electrode Dj through node N201 and transistors Q211 to Q21m. Thereby, the voltage of the data electrode Dj is held at Vd.

  Between time t2 and time t3, after a lapse of a predetermined time from time t2, the control signals S201 to S20m become high level. In this case, the data electrode Dj is at the ground potential as described above.

  After that, at time t4, both the control signals S201 to S20m again become low level. The control signals S201 to S20m are held at a low level from time t4 to time t9. Thereby, the voltage of the data electrode Dj is held at Vd.

  At time t9, the control signals S201 to S20m become high level. Control signals S201 to S20m are held at a high level from time t9 to the end of the initialization period. Thereby, the data electrode Dj is held at the ground potential.

(8) Other Circuit Configuration and Operation Control of Scan Electrode Drive Circuit 53 (8-a) Circuit Configuration In the present embodiment, scan electrode drive circuit 53 having the following configuration may be used. FIG. 15 is a circuit diagram showing another configuration of scan electrode drive circuit 53 of FIG. In the following description, an example of a positive pulse that discharges when the drive voltage rises is shown, but a negative pulse that discharges when the drive voltage falls may be used.

  The scan electrode drive circuit 53 of this example is different from the scan electrode drive circuit 53 of FIG. 9 in the following points.

  As shown in FIG. 15, in the scan electrode driving circuit 53 of this example, the transistor Q15 is connected between the node N14 and the node N18. As in the example of FIG. 9, a control signal S15 is input to the gate.

  The transistor Q14 is connected between the node N15 and the ground terminal, and a control signal S14 is input to the gate. The recovery coil L12 is connected between the node N15 and the node N12b.

(8-b) Operation Control FIG. 16 is a timing chart of the control signals S11 to S22 supplied to the scan electrode drive circuit 53 of FIG. 15 during the initialization period of the first SF of FIG.

  Control signals S11 to S22 given to scan electrode drive circuit 53 in FIG. 15 are the same as control signals S11 to S22 given to scan electrode drive circuit 53 in FIG. 9 except for the following points.

  According to the example of FIG. 16, the control signal S20 is maintained at the high level until the time point t4. In this case, the transistor Q20 is on. Immediately before time t4, the transistors Q11, Q12, Q14, Q15, Q18, Q19, and Q21 are turned off, and the transistors Q13, Q16, Q17, Q20, and Q22 are turned on. Therefore, a current flows from power supply terminal V11 to scan electrode SCi. Thereby, the voltage of scan electrode SCi rises to Vi1.

  At time t4, the control signal S20 becomes low level. Thereby, the transistor Q20 is turned off. At time t5, the control signals S15 and S21 are at a high level, and the control signals S16 and S22 are at a low level. Thereby, the transistors Q15 and Q21 are turned on, and the transistors Q16 and Q22 are turned off.

  In this case, the current flowing from power supply terminal V11 to scan electrode SCi is interrupted, and the current flows from power supply terminal V12 to scan electrode SCi. At this time, since the voltage of the node N16 is held at Vi1, the voltage of the scan electrode SCi gradually rises and becomes Vi2, that is, (Vi1 + Vr) at time t6.

  Next, at time t7, the control signal S15 becomes low level, and the control signals S16 and S19 become high level. Thereby, the transistor Q15 is turned off and the transistors Q16 and Q19 are turned on. In this case, the current flowing from power supply terminal V12 to scan electrode SCi is interrupted, and the current flows from power supply terminal V14 to scan electrode SCi. Thereby, the voltage of scan electrode SCi falls. At this time, since the voltage of the node N16 is held at Vi1, the voltage of the scan electrode SCi is held at (Vi1 + Vs) at time t7a.

  Next, at time t7b, the control signals S19 and S21 become low level, and the control signals S20 and S22 become high level. Thereby, the transistors Q19 and Q21 are turned off, and the transistors Q20 and Q22 are turned on. In this case, the current flowing from power supply terminal V14 to scan electrode SCi is interrupted, and the current flows from power supply terminal V11 to scan electrode SCi. Thereby, the voltage of scan electrode SCi drops to Vi1 at time t8.

  Next, at time t9, the control signals S13 and S17 become low level, and the control signal S18 becomes high level. Thereby, the transistors Q13 and Q17 are turned off and the transistor Q18 is turned on. In this case, the voltage of the scan electrode SCi gradually decreases and becomes the voltage Vi4 of the power supply terminal V13 at time t10.

  At time t10, the control signals S19 and S21 become high level, and the control signals S20 and S22 become low level. Thereby, the transistors Q19 and Q21 are turned on, and the transistors Q20 and Q22 are turned off. As a result, the voltage of scan electrode SCi becomes substantially the ground potential.

(9) Still Another Circuit Configuration and Operation Control of Scan Electrode Drive Circuit 53 (9-a) Circuit Configuration FIG. 17 is a circuit diagram showing still another configuration of scan electrode drive circuit 53 of FIG. In the following description, an example of a positive pulse that discharges when the drive voltage rises is shown, but a negative pulse that discharges when the drive voltage falls may be used. The scan electrode drive circuit 53 of this example is different from the scan electrode drive circuit 53 of FIG. 9 in the following points.

  As shown in FIG. 17, in scan electrode drive circuit 53 of this example, transistors Q19 and Q20 and capacitor C12 provided in scan electrode drive circuit 53 of FIG. 9 are not provided.

  The transistor Q21 is connected between the node N17 and the scan electrode SCi, and a control signal S21 is input to the gate. The transistor Q22 is connected between the node N16 and the scan electrode SCi, and a control signal S22 is input to the gate.

  The recovery coil L12 is connected between the node N15 and the node N12b. A voltage Vr ′ is applied to the power supply terminal V12 instead of the voltage Vr. The voltage Vr ′ is obtained by adding the voltage (Vi1−Vs) to the voltage Vr.

(9-b) Operation Control FIG. 18 is a timing chart of the control signals S11 to S18, S21, and S22 supplied to the scan electrode drive circuit 53 of FIG. 17 during the initialization period of the first SF of FIG.

  As shown in FIG. 18, in the scan electrode drive circuit 53 of FIG. 17, the drive waveform in the initialization period applied to the scan electrode SCi is slightly different from the drive waveform of FIG. First, the drive waveform applied to the scan electrode SCi of this example will be described.

  According to the drive waveform of FIG. 18, after the start of the initialization period, the voltage applied to the scan electrode SCi from time t3 to time t4 rises to Vs and is held.

  Subsequently, from time t5 to time t6, a ramp voltage that gradually rises from the voltage Vs by the voltage Vr ′ is applied to the scan electrode SCi. From time t6 to time t7, the voltage applied to the scan electrode SCi is held at (Vs + Vr ′).

  From time t7 to time t7a, the voltage applied to scan electrode SCi drops by voltage Vr 'and is held at (Vs + Vi1). Thereafter, from time t7b to time t8, the voltage applied to scan electrode SCi drops by voltage Vs and is held at Vi1.

  Next, from time t9 to time t10, a ramp voltage that decreases from voltage Vi1 to negative voltage Vi4 is applied to scan electrode SCi. Finally, at time 10, the voltage of the scan electrode SCi is raised from Vi4 to almost the ground potential and held. In this state, the initialization period ends.

  As described above, the following control signals S11 to S18, S21, and S22 are applied to the scan electrode drive circuit 53 of FIG. 17 in order to obtain the drive waveform applied to the scan electrode SCi.

  At the start time t2 of the first SF, the control signals S11, S12, S13, S15, S18, S19, and S21 are each at a low level. Thereby, the transistors Q11, Q12, Q13, Q15, Q18, and Q21 are turned off.

  Further, the control signals S14, S16, S17, and S22 are each at a high level. Thereby, the transistors Q14, Q16, Q17, and Q22 are turned on. In this case, scan electrode SCi is held at the ground potential.

  At time t3, the control signal S21 becomes high level, and the control signals S14 and S22 become low level. Thereby, the transistor Q21 is turned on and the transistors Q14 and Q22 are turned off. Thereby, the voltage of scan electrode SCi rises to Vs.

  At time t5, the control signal S15 becomes high level, and the control signal S16 becomes low level. Thereby, the transistor Q15 is turned on and the transistor Q16 is turned off. As a result, the voltage of the scan electrode SCi gradually increases from Vs by the voltage Vr ′, and reaches (Vs + Vr ′) at time t6. At time t6, the control signal S13 becomes high level. Thereby, the transistor Q13 is turned on. From time t5 to time t6, the voltage of the scan electrode SCi is held at (Vs + Vr ′).

  Next, at time t7, the control signal S15 becomes low level, and the control signal S16 becomes high level. Thereby, the transistor Q15 is turned off and the transistor Q16 is turned on. As a result, the voltage of the scan electrode SCi drops by Vr ′ and becomes (Vs + Vi1) at time t7a. From time t7a to time t7b, the voltage of scan electrode SCi is held at (Vs + Vi1).

  At time t7b, the control signal S21 becomes low level, and the control signal S22 becomes high level. Thereby, the transistor Q21 is turned off and the transistor Q22 is turned on. In this case, the voltage of the scan electrode SCi drops by Vs and becomes Vi1 at time t8. From time t8 to time t9, the voltage of scan electrode SCi is held at Vi1.

  At time t9, the control signals S13 and S17 become low level, and the control signal S18 becomes high level. Thereby, the transistors Q13 and Q17 are turned off and the transistor Q18 is turned on. In this case, the voltage of the scan electrode SCi gradually decreases and becomes the voltage Vi4 of the power supply terminal V13 at time t10.

  At time t10, the control signal S21 becomes high level and the transistor Q21 is turned on. Thereby, the voltage Vs of the power supply terminal V14 is applied to the scan electrode SCi, so that the voltage of the scan electrode SCi becomes almost the ground potential.

  In the above configuration, a ramp waveform (not shown) that changes in a curve may be applied to the scan electrode SCi by adjusting the capacitance of the capacitor C13, for example.

(10) Effect In the plasma display device according to the present embodiment, the time t3 (FIGS. 5, 6, and 8) when the scan electrode SCi rises to the positive voltage Vi1 in the initialization period in which the all-cell initialization operation is performed. ), A positive voltage Vd is applied to the data electrode Dj. As a result, a strong discharge is generated between sustain electrode SUi and data electrode Dj.

  Therefore, even when a lot of negative wall charges remain on the sustain electrode SUi due to the weak erasing discharge before the initialization of all the cells, the voltage between the scan electrode SCi and the sustain electrode SUi is applied when the ramp voltage is applied to the scan electrode SCi. Generation of strong discharge is prevented.

  As a result, an appropriate amount of wall charges remains on scan electrode SCi, so that the voltage between scan electrode SCi and sustain electrode SUi surely exceeds the discharge start voltage as the ramp voltage increases. As a result, a weak initializing discharge is generated between scan electrode SCi and sustain electrode SUi in the initializing period, and the wall charges on each electrode SCi, SUi are reliably adjusted to a desired amount.

  Further, since the data electrode Dj is held at the voltage Vd while the ramp voltage rises slowly, it is possible to prevent a strong discharge from occurring between the scan electrode SCi and the data electrode Dj.

  Further, the wall charge on scan electrode SCi and the wall charge on sustain electrode SUi are reduced by a weak erasing discharge between scan electrode SCi and sustain electrode SUi before the start of the initialization period. Accordingly, a large amount of positive wall charges can be left in scan electrode SCi, and a large amount of negative wall charges can be left in sustain electrode SUi. Therefore, in the address period after the initialization period, address discharge between scan electrode SCi and data electrode Di and between sustain electrode SUi and scan electrode SCi is weakened. As a result, even when the distance between adjacent discharge cells DC is small, it is possible to prevent crosstalk from occurring between adjacent discharge cells DC.

(11) Others (11-a)
For example, as shown in FIG. 5, in this plasma display device, a pulsed positive voltage Vd is applied to the data electrode Dj at the start time t2 of the initialization period. This is because the data electrode Dj is held at the ground potential when the ramp voltage rising from Vi1 to Vi2 is applied to the scan electrode SCi at the time point t3. This prevents the occurrence of ripples when the lamp voltage rises. Thereby, an IC (integrated circuit) having a low withstand voltage can be used for the plasma display device.

  Therefore, when the withstand voltage of an IC (integrated circuit) constituting the plasma display device is high, the positive voltage Vd applied to the data electrode Dj may not be pulsed. That is, the positive voltage Vd may be continuously applied to the data electrode Dj while the ramp voltage is applied to the scan electrode SCi (for example, from the time t2 to the time t9).

(11-b)
In the above embodiment, in the data electrode drive circuit 52, the scan electrode drive circuit 53, and the sustain electrode drive circuit 54, n-channel FETs and p-channel FETs are used as switching elements, but the switching elements are not limited to these. .

  For example, in each of the above circuits, a p-channel FET or IGBT (insulated gate bipolar transistor) may be used instead of the n-channel FET, or an n-channel FET or IGBT (insulated gate bipolar) instead of the p-channel FET. Transistor) or the like may be used.

(12) Correspondence between each constituent element of claim and each element of the embodiment Hereinafter, an example of correspondence between each constituent element of the claim and each element of the embodiment will be described. It is not limited to.

  In the above embodiment, the voltage Vi1 and the voltage Vs in FIG. 18 are examples of the first potential, the voltage Vi2 and the voltage (Vs + Vr ′) in FIG. 18 are examples of the second potential, and the voltage Ve1 is the third potential. , The ground potential is an example of the fourth potential, the ground potential is an example of the fifth potential, the voltage Vd is an example of the sixth potential, and the voltage Vs is the seventh potential. 5, FIG. 6, and FIG. 8 is an example of the time point when the change of the scan electrode to the first potential starts.

  The present invention can be used in a display device that displays various images.

Claims (8)

A plasma display apparatus for driving a plasma display panel having a plurality of discharge cells at intersections of scan electrodes and sustain electrodes and a plurality of data electrodes by a subfield method in which one field period includes a plurality of subfields,
A scan electrode driving circuit for driving the scan electrode;
A sustain electrode driving circuit for driving the sustain electrode;
A data electrode driving circuit for driving the data electrode,
At least one subfield of the plurality of subfields includes an initialization period for adjusting wall charges of the plurality of discharge cells to a state in which address discharge is possible,
The scan electrode driving circuit applies a ramp voltage that changes from a first potential to a second potential for the initialization discharge in the initialization period to the scan electrode,
The sustain electrode drive circuit changes the third potential to the fourth potential so that a potential difference between the scan electrode and the sustain electrode becomes larger before the start of the change of the scan electrode to the first potential. A voltage that changes to a potential is applied to the sustain electrode,
In the data electrode driving circuit, the potential difference between the scan electrode and each data electrode is small in synchronization with the change in the voltage of the sustain electrode before the start of the change of the scan electrode to the first potential. A plasma display device that applies a voltage changing from the fifth potential to the sixth potential to each data electrode. The data electrode driving circuit changes the voltage of each data electrode from the sixth potential to the fifth potential before the start of the change of the scan electrode to the first potential, and then performs the scan. The plasma display device according to claim 1, wherein the voltage of each data electrode is returned to the sixth potential again after the start of the change of the electrode to the first potential. The plasma display apparatus according to claim 1, wherein the data electrode drive circuit maintains the voltage of each data electrode at the sixth potential during the application of the ramp voltage. The second potential is a positive potential higher than the first potential,
The third potential is a positive potential higher than the fourth potential;
The plasma display apparatus according to claim 1, wherein the sixth potential is a positive potential higher than the fifth potential. The fourth potential and the sixth potential are set so that a first discharge is generated between the sustain electrode and each data electrode,
The ramp voltage is set such that a second discharge is generated between the scan electrode and the sustain electrode during the change from the first potential to the second potential after the first discharge. ,
The plasma display apparatus according to claim 1, wherein a discharge current during the second discharge is smaller than a discharge current during the first discharge. The scan electrode driving circuit applies a pulse voltage having a seventh potential to the scan electrode at the end of the sustain period preceding the initialization period,
The sustain electrode driving circuit applies, to the sustain electrode, a voltage that changes from the fourth potential to the third potential during the period of the pulse voltage in order to reduce wall charges of the discharge cells that have undergone sustain discharge. The plasma display device according to claim 1, which is applied. The scan electrode driving circuit scans a ramp pulse voltage having a seventh potential at the end of the sustain period prior to the initialization period in order to reduce wall charges of discharge cells that have undergone sustain discharge. Applied to the electrode,
The leading edge of the ramp pulse voltage changes more slowly than the trailing edge;
The plasma display apparatus according to claim 1, wherein the sustain electrode driving circuit holds the sustain electrode at the third potential during the ramp pulse voltage. A plasma display apparatus driving method for driving a plasma display panel having a plurality of discharge cells at intersections of scan electrodes, sustain electrodes and a plurality of data electrodes by a subfield method in which one field period includes a plurality of subfields. And
Driving the scan electrode;
Driving the sustain electrode;
Driving the data electrode,
At least one subfield of the plurality of subfields includes an initialization period for adjusting wall charges of the plurality of discharge cells to a state in which address discharge is possible,
The step of driving the scan electrode includes the step of applying to the scan electrode a ramp voltage that changes from a first potential to a second potential for initialization discharge in the initialization period,
The step of driving the sustain electrode is performed from the third potential so that a potential difference between the scan electrode and the sustain electrode is increased before the start of the change of the scan electrode to the first potential. Applying a voltage that changes to a potential of 4 to the sustain electrode;
The step of driving the data electrode includes a potential difference between the scan electrode and each data electrode in synchronization with a change in the voltage of the sustain electrode before the start of the change of the scan electrode to the first potential. Applying a voltage that changes from the fifth potential to the sixth potential to each data electrode so as to decrease the voltage.

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